hh.sePublications
Change search
Refine search result
123 1 - 50 of 131
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Aghaeipour, Mahtab
    et al.
    Lund University, Lund, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Lund University, Lund, Sweden.
    Enhanced broadband absorption in nanowire arrays with integrated Bragg reflectors2018In: Nanophotonics, E-ISSN 2192-8614, Vol. 7, no 5, p. 819-825Article in journal (Refereed)
    Abstract [en]

    A near-unity unselective absorption spectrum is desirable for high-performance photovoltaics. Nanowire arrays are promising candidates for efficient solar cells due to nanophotonic absorption resonances in the solar spectrum. The absorption spectra, however, display undesired dips between the resonance peaks. To achieve improved unselective broadband absorption, we propose to enclose distributed Bragg reflectors (DBRs) in the bottom and top parts of indium phosphide (InP) nanowires, respectively. We theoretically show that by enclosing only two periods of In0.56Ga0.44As/InPDBRs, an unselective 78% absorption efficiency (72% for nanowires without DBRs)is obtained at normal incidence in the spectral range from 300 nm to 920 nm. Under oblique light incidence, the absorption efficiency is enhanced up to about 85% at an incidence angle of 50º. By increasing the number of DBR periods from two to five, the absorption efficiency is further enhanced up to 95% at normal incidence. In this work we calculated optical spectra for InP nanowires, but the results are expected to be valid for other direct band gap III-V semiconductor materials. We believe that our proposed idea of integrating DBRs in nanowires offers great potential for high-performance photovoltaic applications. ©2018 Håkan Pettersson et al., published by De Gruyter, Berlin/Boston.

    Download full text (pdf)
    fulltext
  • 2.
    AL, Cihan
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Koroglu, Kubra
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Detection of the Change Point and Optimal Stopping Time by Using Control Charts on Energy Derivatives2011Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Download full text (pdf)
    Cihan.AL_K.Koroglu_master_thesis
  • 3.
    Amin, Mohammed Nurul
    et al.
    Halmstad University, School of Information Technology. amin _ m 154@yahoo.com.
    Alam, Md. Obaidul
    Halmstad University, School of Information Technology. obai_ aust@yahoo.com.
    Landin, Lars
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Electrical and optical characteristics of Infrared Photodetectors based on InP nanowire2011In: 14th International Conference on Computer and Information Technology, ICCIT 2011, p. 629-634, article id 6164864Article in journal (Refereed)
    Abstract [en]

    High speed photodetectors are most sophisticated optoelectronic devices, because it has high photo sensitivity, and allow a large wavelength range of detection as a receiver from 750 nm to 1.3-1.55 μm in the optical communication system. Since the last decade, the electrical and optical characteristics of photodetectors have been investigated to improve their performance and price. We have worked on two different type of infrared photodetectors based on nanowire. One photodetector was p-n photodiode, and the other one was p-i-n structure. We investigated the detector performance at 77K-300K temperature corresponding with wavelength in darkness and under illumination as regarding breakdown voltage, sensitivity, and quantum efficiency. We have also compared the differences between the two photodetectors performance characteristics. © 2011 IEEE.

  • 4.
    Andersen, Emelie
    et al.
    Halmstad University, School of Business, Engineering and Science.
    Nilsson, Bertil
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Sahlén, Göran
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS).
    Survival possibilities of the dragonfly Aeshna viridis (Insecta, Odonata) in southern Sweden predicted from dispersal possibilities2016In: Journal of Insect Conservation, ISSN 1366-638X, E-ISSN 1572-9753, Vol. 20, no 2, p. 179-188Article in journal (Refereed)
    Abstract [en]

    We use public records from 1980 to 2014 to analyse survival of the EU Annex IV species Aeshna viridis in Sweden, a dragonfly strongly associated with the plant Stratiotes aloides. We clustered localities with S. aloides based on assumed dispersal abilities of A. viridis, using a dispersing radius of 2–100 km, calculating the proportion of sites with S. aloides that A. viridis is able to reach. If mean dispersal capability is high (40 km or above) 92.6 % or more of the localities are connected. For a good disperser, the probability of long-time survival is good. We further analysed the species richness of other Odonata and aquatic plants at 98 localities from the dataset. A. viridis co-occurred with more Odonata in the presence of S. aloides and running water but not in lakes. S. aloides sites had a higher number of other aquatic plants. Area had no impact on the occurrence of the species. For the present situation we surveyed 32 localities with known occurrence of the species. Only half of the sites for S. aloides contained any specimens while A. viridis occurred in the same number of sites. The species co-occurred in only 8 of 32 sites. In four sites A. viridis larvae appeared among Menyanthes trifoliata, Phragmites australis, Potamogeton natans and Sphagnum spp., indicating that at high latitudes A. viridis breeds among other species. Indirect monitoring based only on S. aloides would underestimate the number of populations of the dragonfly. © 2016 Springer International Publishing Switzerland

  • 5.
    Anokhina, Ksenia
    et al.
    Avd. f. Fasta Tillståndets Fysik, Lunds Universitet, Lund, Sweden.
    Graczyk, Mariousz
    Avd. f. Fasta Tillståndets Fysik, Lunds Universitet, Lund, Sweden.
    Kvennefors, Anders
    Avd. f. Fasta Tillståndets Fysik, Lunds Universitet, Lund, Sweden.
    Montelius, Lars
    Avd. f. Fasta Tillståndets Fysik, Lunds Universitet, Lund, Sweden.
    Maximov, Ivan
    Avd. f. Fasta Tillståndets Fysik, Lunds Universitet, Lund, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Metal-assisted chemical etching of Si for fabrication of nanoimprint stamps2011Conference paper (Refereed)
  • 6.
    Antczak, Magdalena
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Leniec, Marta
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Pricing and Hedging of Defaultable Models2011Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Modelling defaultable contingent claims has attracted a lot of interest in recent years, motivated in particular by the Late-2000s Financial Crisis. In several papers various approaches on the subject have been made. This thesis tries to summarize these results and derive explicit formulas for the prices of financial derivatives with credit risk. It is divided into two main parts. The first one is devoted to the well-known theory of modelling the default risk while the second one presents the results concerning pricing of the defaultable models that we obtained ourselves.

    Download full text (pdf)
    Pricing and Hedging of Defaultable Models
  • 7.
    Arashlouzadeh, Amir
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Surface Roughness Measurment: Multi-bandFrequency Shift Interferometer based onPolarization Measurement2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Optical measurement techniques have been gaining ground for their vast applications in industry and scientific purposes. These techniques are beneficial comparing to the mechanical methods. Non-intrusive, robust, high accuracy and small measurement volume are some of the advantages of the optical metrology. However, these approaches are expensive. Interferometry is one of the most prominent principles of these optical measurements. It employs the study of fringe patterns in order to model surface roughness with a high precision up to nano-meter scale. In this thesis, we mainly focus on the multi-band frequency shifting interferometry based on polarization measurement for 3D surface modeling. The system has advantages such as it is very accurate and there is no need of a phase unwrapping algorithm. Like the conventional phase shifting interferometry, four intensity images are recorded for the four polarization states correspondingly and then the images are processed by MATLAB and the final results are provided. In this technique the need for three cameras and offset correction between the cameras has been revised and optimized by using only one camera. In the first setup trial, a fiber optic switch has been used which does not lead to the desired results and then the switch has been removed and the corresponding images are satisfactory.

    Download full text (pdf)
    fulltext
  • 8.
    Belova, Anna
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Shmidt, Tamara
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Meshfree methods in option pricing2011Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A meshfree approximation scheme based on the radial basis function methods is presented for the numerical solution of the options pricing model. This thesis deals with the valuation of the European, Barrier, Asian, American options of a single asset and American options of multi assets. The option prices are modeled by the Black-Scholes equation. The θ-method is used to discretize the equation with respect to time. By the next step, the option price is approximated in space with radial basis functions (RBF) with unknown parameters, in particular, we con- sider multiquadric radial basis functions (MQ-RBF). In case of Ameri- can options a penalty method is used, i.e. removing the free boundary is achieved by adding a small and continuous penalty term to the Black- Scholes equation. Finally, a comparison of analytical and finite difference solutions and numerical results from the literature is included.

    Download full text (pdf)
    fulltext
  • 9.
    Berg, Alexander
    et al.
    Lund University, Lund, Sweden.
    Yazdi, Sadegh
    Technical University of Denmark, Lyngby, Denmark.
    Nowzari, Ali
    Lund University, Lund, Sweden.
    Storm, Kristian
    Lund University, Lund, Sweden.
    Jain, Vishal
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Lund University, Lund, Sweden.
    Vainorius, Neimantas
    Lund University, Lund, Sweden.
    Samuelson, Lars
    Lund University, Lund, Sweden.
    Wagner, Jakob B.
    Technical University of Denmark, Lyngby, Denmark.
    Borgström, Magnus T.
    Lund University, Lund, Sweden.
    Radial Nanowire Light-Emitting Diodes in the (AlxGa1-x)yIn1-yP Material System2016In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 16, no 1, p. 656-662Article in journal (Refereed)
    Abstract [en]

    Nanowires have the potential to play an important role for next-generation light-emitting diodes. In this work, we present a growth scheme for radial nanowire quantum-well structures in the AlGaInP material system using a GaInP nanowire core as a template for radial growth with GaInP as the active layer for emission and AlGaInP as charge carrier barriers. The different layers were analyzed by X-ray diffraction to ensure lattice-matched radial structures. Furthermore, we evaluated the material composition and heterojunction interface sharpness by scanning transmission electron microscopy energy dispersive X-ray spectroscopy. The electro-optical properties were investigated by injection luminescence measurements. The presented results can be a valuable track toward radial nanowire light-emitting diodes in the AlGaInP material system in the red/orange/yellow color spectrum. © 2015 American Chemical Society.

  • 10.
    Bordag, Ljudmila A.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    On Option-Valuation in Illiquid Markets: Invariant Solutions to a Nonlinear Model2008In: Mathematical control theory and finance / [ed] Andrey Sarychev; et al, Berlin: Springer Berlin/Heidelberg, 2008, p. 71-94Conference paper (Other academic)
    Abstract [en]

    The present model describes a perfect hedging strategy for a large trader. In this case the hedging strategy affects the price of the underlying security. The feedback-effect leads to a nonlinear version of the Black-Scholes partial differential equation. Using Lie group theory we reduce in special cases the partial differential equation to some ordinary differential equations. The Lie group found for the model equation gives rise to invariant solutions. Families of exact invariant solutions for special values of parameters are described. © 2008 Springer-Verlag Berlin Heidelberg.

    Download full text (pdf)
    FULLTEXT01
  • 11.
    Bordag, Ljudmila A.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Pricing options in illiquid markets: optimal systems, symmetry reductions and exact solutions2010In: Lobachevskii Journal of Mathematics, ISSN 1995-0802, E-ISSN 1818-9962, Vol. 31, no 2, p. 90-99Article in journal (Refereed)
    Abstract [en]

    We study a class of nonlinear pricing models which involves the feedback effect from the dynamic hedging strategies on the price of asset introduced by  Sircar and Papanicolaou. We are first to study the case of a nonlinear demand function involved in the model. Using a Lie group analysis we investigate the symmetry properties of these nonlinear diffusion equations. We provide the optimal systems of subalgebras and the complete set of non-equivalent reductions of studied PDEs to ODEs. In most cases we obtain families of exact solutions or derive particular solutions to the equations.

    Download full text (pdf)
    FULLTEXT01
  • 12.
    Bordag, Ljudmila A.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Study of the risk-adjusted pricing methodology model with methods of geometrical analysis2011In: Stochastics: An International Journal of Probablitiy and Stochastic Processes, ISSN 1744-2508, E-ISSN 1744-2516, Vol. 83, no 4-6, p. 333-345Article in journal (Refereed)
    Abstract [en]

    Families of exact solutions are found to a nonlinear modification of the Black-Scholes equation. This risk-adjusted pricing methodology model (RAPM) incorporates both transaction costs and the risk from a volatile portfolio. Using the Lie group analysis we obtain the Lie algebra admitted by the RAPM equation. It gives us the possibility to describe an optimal system of subalgebras and the corresponding set of invariant solutions to the model. In this way we can describe the complete set of possible reductions of the nonlinear RAPM model. Reductions are given in the form of different second order ordinary differential equations. In all cases we provide exact solutions to these equations in an explicit or parametric form. Each of these solutions contains a reasonable set of parameters which allows one to approximate a wide class of boundary conditions. We discuss the properties of these reductions and the corresponding invariant solutions.

    Download full text (pdf)
    fulltext
  • 13.
    Bordag, Ljudmila A.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Symmetry reductions and exact solutions for nonlinear diffusion equations2009In: International Journal of Modern Physics A, ISSN 0217-751X, E-ISSN 1793-656X, Vol. 24, no 8/9, p. 1713-1716Article in journal (Refereed)
    Abstract [en]

    The symmetry properties of nonlinear diffusion equations are studied using a Lie group analysis. Reductions and families of exact solutions are found for some of these equations.

    © 2009 World Scientific Publishing Company.

    Download full text (pdf)
    FULLTEXT01
  • 14.
    Bordag, Ljudmila A.
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Chmakova, A. Y.
    Fakultät Mathematik, Naturwissenschaften und Informatik, Brandenburgische Technische Universität Cottbus, Cottbus, Germany.
    Explicit solutions for a nonlinear model of financial derivatives2007In: International Journal of Theoretical and Applied Finance, ISSN 0219-0249, Vol. 10, no 1, p. 1-21Article in journal (Refereed)
    Abstract [en]

    Families of explicit solutions are found to a nonlinear Black-Scholes equation which incorporates the feedback-effect of a large trader in case of market illiquidity. The typical solution of these families will have a payoff which approximates a strangle. These solutions were used to test numerical schemes for solving a nonlinear Black-Scholes equation. © World Scientific Publishing Company.

  • 15.
    Bordag, Ljudmila A.
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Frey, Rüdiger
    Leipzig University, Leipzig, Germany.
    Pricing options in illiquid markets: Symmetry reductions and exact solutions2008In: Nonlinear Models in Mathematical Finance: New Research Trends in Option Pricing / [ed] Matthias Ehrhardt, New York: Nova Science Publishers, Inc., 2008, p. 103-129Chapter in book (Other academic)
    Abstract [en]

    The present paper is concerned with nonlinear Black Scholes equations arising in certain option pricing models with a large trader and/or transaction costs. In the first part we give an overview of existing option pricing models with frictions. While the financial setup differs between models, it turns out that in many of these models derivative prices can be characterized by fully nonlinear versions of the standard parabolic Black-ScholesPDE. In the second part of the paper we study a typical nonlinear Black-Scholes equation using methods from Lie group analysis. The equation possesses a rich symmetry group. By introducing invariant variables,  invariant solutions can therefore be characterized in terms of solutions to ordinary differential equations. Finally we discuss properties and applications of these solutions.

    Download full text (pdf)
    FULLTEXT01
  • 16.
    Bordag, Ljudmila A.
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Matveev, Sergey K.
    St. Petersburger State University.
    Berechnungen der Gleichgewichtslage der Welle unterpräzisierten geometrischen Voraussetzungen der Druckfluidströmung in LHS 7502009Report (Other academic)
  • 17.
    Bordag, Ljudmila A.
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Matveev, Sergey K.
    St. Petersburg State University.
    Erste  Berechnungen der Druckfluidströmung2008Report (Other academic)
  • 18.
    Bordag, Ljudmila A.
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Matveev, Sergey K.
    St. Petersburg State University.
    Präzisierte Berechnungender Druckfluidströmung in LHS 7502008Report (Other academic)
  • 19.
    Bordag, Ljudmila A.
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Mikaelyan, Anna
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Models of self-financing hedging strategies in illiquid markets: Symmetry reductions and exact solutions2011In: Letters in Mathematical Physics, ISSN 0377-9017, E-ISSN 1573-0530, Vol. 96, no 1-3, p. 191-207Article in journal (Refereed)
    Abstract [en]

    We study the general model of self-financing trading strategies inilliquid markets introduced by Schoenbucher and Wilmott, 2000.A hedging strategy in the framework of this model satisfies anonlinear partial differential equation (PDE) which contains somefunction g(alpha). This function is deep connected to anutility function.

    We describe the Lie symmetry algebra of this PDE and provide acomplete set of reductions of the PDE to ordinary differentialequations (ODEs). In addition we are able to describe all types offunctions g(alpha) for which the PDE admits an extended Liegroup. Two of three special type functions lead to modelsintroduced before by different authors, one is new. We clarify theconnection between these three special models and the generalmodel for trading strategies in illiquid markets. We study withthe Lie group analysis the new special case of the PDE describingthe self-financing strategies. In both, the general model and thenew special model, we provide the optimal systems of subalgebrasand study the complete set of reductions of the PDEs to differentODEs. In all cases we are able to provide explicit solutions tothe new special model. In one of the cases the solutions describepower derivative products.

    Download full text (pdf)
    fulltext
  • 20.
    Bordag, Michael
    et al.
    Leipzig University, Institute for Theoretical Physics, Leipzig, Germany.
    Jede, Ralf
    Raith GmbH, Dortmund, Germany.
    Montelius, Lars
    Lunds University, Physics Department, Lund, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Riu, Jordi
    University Rovira i Vergili, Taragona, Spain.
    Schmucker, Ulrich
    University Rovira i Vergili, Taragona, Spain.
    Zubtsov, Michael
    Fraunhofer Institute for Factory Automation, Magdeburg, Germany.
    Parallel nano-assembly directed by short-range field forces2006In: Proceedings of the 1st IEEE International Conference on Nano/Micro Engineered and Molecular Systems, Piscataway, United States: IEEE Press, 2006, p. 620-622, article id 4135031Conference paper (Refereed)
    Abstract [en]

    We present the ECs Sixth Framework Programme PARNASS project, which stands for 'Parallel nano assembling directed by short-range field forces' and represents a radical innovative approach to fabricating large volumes of hybrid nano electronic devices. The project combines in a synergy the 'top-down' and 'bottom-up' methods addressing one of the challenging physical and engineering problems of the very high accuracy over a large area. An array of specially designed nano-scale force field sources has to be a key part of this innovative approach to large-scale nano manufacturing. © 2006 IEEE.

  • 21.
    Borschel, Christian
    et al.
    Institute for Solid State Physics, Jena University, Max-Wien-Platz 1, 07743 Jena, Germany.
    Messing, Maria
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Borgström, Magnus T.
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Paschoal, Waldomiro
    Avd. f. Fasta tillståndets fysik, Lunds Universitet / Tillämpad matematik och fysik (MPE-lab), MPE-lab.
    Wallentin, Jesper
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Kumar, Sandeep
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Mergenthaler, Kilian
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Deppert, Knut
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Canali, C. M.
    Högskolan i Kalmar.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Samuelson, Lars
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Ronning, Carsten
    Institute for Solid State Physics, Jena University, Max-Wien-Platz 1, 07743 Jena, Germany.
    A New Route toward Semiconductor Nanospintronics: Highly Mn-Doped GaAs Nanowires Realized by Ion-Implantation under Dynamic Annealing Conditions2011In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 11, no 9, p. 3935-3940Article in journal (Refereed)
    Abstract [en]

    We report on highly Mn-doped GaAs nanowires (NWs) of high crystalline quality fabricated by ion beam implantation, a technique that allows doping concentrations beyond the equilibrium solubility limit. We studied two approaches for the preparation of Mn-doped GaAs NWs: First, ion implantation at room temperature with subsequent annealing resulted in polycrystalline NWs and phase segregation of MnAs and GaAs. The second approach was ion implantation at elevated temperatures. In this case, the single-crystallinity of the GaAs NWs was maintained, and crystalline, highly Mn-doped GaAs NWs were obtained. The electrical resistance of such NWs dropped with increasing temperature (activation energy about 70 meV). Corresponding magnetoresistance measurements showed a decrease at low temperatures, indicating paramagnetism. Our findings suggest possibilities for future applications where dense arrays of GaMnAs nanowires may be used as a new kind of magnetic material system.

  • 22.
    Borschel, Christian
    et al.
    Institute for Solid State Physics, University of Jena, Jena, Germany.
    Messing, Maria
    Lund University, Lund, Sweden.
    Mergenthaler, Kilian
    Lund University, Lund, Sweden.
    Borgström, Magnus T.
    Lund University, Lund, Sweden.
    Paschoal, Waldomiro
    Lund University, Lund, Sweden.
    Wallentin, Jesper
    Lund University, Lund, Sweden.
    Kumar, Sandeep
    Lund University, Lund, Sweden.
    Deppert, Knut
    Lund University, Lund, Sweden.
    Canali, Carlo
    Linnaeus University, Kalmar, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Samuelson, Lars
    Lund University, Lund, Sweden.
    Ronning, Carsten
    Institute for Solid State Physics, University of Jena, Jena, Germany.
    A New Route towards Semiconductor Nanospintronics: Highly Mn-Doped GaAs Nanowires Realized by Ion-Implantation under Dynamic Annealing Conditions2011Conference paper (Refereed)
  • 23.
    Bukina, Elena
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Efficient Numerical Solution of PIDEs in Option Pricing2011Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
    Download full text (pdf)
    PIDE
  • 24.
    Burnos, Sergey
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE). Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Ngow, ChaSing
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE). Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    SVI estimation of the implied volatility by Kalman filter.2010Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    To understand and model the dynamics of the implied volatility smile is essential for trading, pricing and risk management portfolio. We suggest a  linear Kalman filter for updating of the Stochastic Volatility Inspired (SVI) model of the volatility. From a risk management perspective we generate the 1-day ahead forecast of profit and loss (P\&L) of option portfolios. We compare the estimation of the implied volatility using the SVI model with the cubic polynomial model. We find that the SVI Kalman filter has outperformed the  others.

    Download full text (pdf)
    FULLTEXT01
  • 25.
    Campanini, D.
    et al.
    Department of Physics, Stockholm University, Stockholm, SE-106 91, Sweden.
    Diao, Zhu
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Rydh, Andreas
    Department of Physics, Stockholm University, Stockholm, SE-106 91, Sweden.
    Raising the superconducting Tc of gallium: In situ characterization of the transformation of α -Ga into β -Ga2018In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 97, no 18, article id 184517Article in journal (Refereed)
    Abstract [en]

    Gallium (Ga) displays several metastable phases. Superconductivity is strongly enhanced in the metastable β-Ga with a critical temperature Tc=6.04(5)K, while stable α-Ga has a much lower Tc<1.2K. Here we use a membrane-based nanocalorimeter to initiate the transition from α-Ga to β-Ga on demand, as well as study the specific heat of the two phases on one and the same sample. The in situ transformation is initiated by bringing the temperature to about 10K above the melting temperature of α-Ga. After such treatment, the liquid supercools down to 232K, where β-Ga solidifies. We find that β-Ga is a strong-coupling type-I superconductor with Δ(0)/kBTc=2.00(5) and a Sommerfeld coefficient γn=1.53(4)mJ/molK2, 2.55 times higher than that in the α phase. The results allow a detailed comparison of fundamental thermodynamic properties between the two phases. © 2018 American Physical Society.

  • 26.
    Chalangar, Ebrahim
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Linköping University, Norrköping, Sweden.
    Machhadani, Houssaine
    Linköping University, Linköping, Sweden.
    Lim, Seung-Hyuk
    Linköping University, Linköping, Sweden.
    Karlsson, K. Fredrik
    Linköping University, Linköping, Sweden.
    Nur, Omer
    Linköping University, Norrköping, Sweden.
    Willander, Magnus
    Linköping University, Norrköping, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Linköping University, Norrköping, Sweden & Lund University, Lund, Sweden.
    Influence of morphology on electrical and optical properties of graphene/Al-doped ZnO-nanorod composites2018In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 29, no 41, article id 415201Article in journal (Refereed)
    Abstract [en]

    The development of future 3D-printed electronics relies on the access to highly conductive inexpensive materials that are printable at low temperatures (<100 C). The implementation of available materials for these applications are, however, still limited by issues related to cost and printing quality. Here, we report on the simple hydrothermal growth of novel nanocomposites that are well suited for conductive printing applications. The nanocomposites comprise highly Al-doped ZnO nanorods grown on graphene nanoplatelets (GNPs). The ZnO nanorods play the two major roles of (i) preventing GNPs from agglomerating and (ii) promoting electrical conduction paths between the graphene platelets. The effect of two different ZnO-nanorod morphologies with varying Al-doping concentration on the nanocomposite conductivity and the graphenedispersity are investigated. Time-dependent absorption, photoluminescence and photoconductivity measurements show that growth in high pH solutions promotes a better graphene dispersity, higher doping levels and enhanced bonding between the graphene and the ZnO nanorods. Growth in low pH solutions yields samples characterized by a higher conductivity and a reduced number of surface defects. These samples also exhibit a large persistent photoconductivity attributed to an effective charge separation and transfer from the nanorods to the graphene platelets. Our findings can be used to tailor the conductivity of novel printable composites, or for fabrication of large volumes of inexpensive porous conjugated graphene-semiconductor composites. © 2018 IOP Publishing Ltd.

    Download full text (pdf)
    fulltext
  • 27.
    Chalangar, Ebrahim
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Department of Science and Technology, Linköping University, Norrköping, Sweden.
    Nur, Omer
    Department of Science and Technology, Linköping University, Norrköping, Sweden.
    Willander, Magnus
    Department of Science and Technology, Linköping University, Norrköping, Sweden.
    Gustafsson, Anders
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Department of Science and Technology, Linköping University, Norrköping, Sweden & Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Synthesis of Vertically Aligned ZnO Nanorods Using Sol-gel Seeding and Colloidal Lithography Patterning2021In: Nanoscale Research Letters, ISSN 1931-7573, E-ISSN 1556-276X, Vol. 16, no 1, article id 46Article in journal (Refereed)
    Abstract [en]

    Different ZnO nanostructures can be grown using low-cost chemical bath deposition. Although this technique is cost-efficient and flexible, the final structures are usually randomly oriented and hardly controllable in terms of homogeneity and surface density. In this work, we use colloidal lithography to pattern (100) silicon substrates to fully control the nanorods' morphology and density. Moreover, a sol-gel prepared ZnO seed layer was employed to compensate for the lattice mismatch between the silicon substrate and ZnO nanorods. The results show a successful growth of vertically aligned ZnO nanorods with controllable diameter and density in the designated openings in the patterned resist mask deposited on the seed layer. Our method can be used to fabricate optimized devices where vertically ordered ZnO nanorods of high crystalline quality are crucial for the device performance. © 2021 BioMed Central Ltd

  • 28.
    Conache, Gabriela
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Gray, Struan M.
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Bordag, Michael
    Institute for Theoretical Physics, Leipzig University.
    Ribayrol, Aline
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Fröberg, Linus
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Samuelson, Lars
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Montelius, Lars
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    AFM-based manipulation of InAs nanowires2008In: Proceedings of the IVC-17 (17th International Vacuum Congress) [also] ICSS-13 (13th International Conference on Surface Science) [also] ICN+T-2007 (International Conference on Nanoscience and Technology): 2-6 July 2007, Stockholm, Sweden, Bristol: Institute of Physics (IOP), 2008, Vol. 100, no 5, 1, p. 052051-052051-4Conference paper (Refereed)
    Abstract [en]

    A controlled method of manipulation of nanowires was found using the tip of an Atomic Force Microscope (AFM). Manipulation is done in the ‘Retrace Lift’ mode, where feedback is turned off for the reverse scan and the tip follows a nominal path. The effective manipulation force during the reverse scan can be changed by varying an offset in the height of the tip over the surface. Using this method, we have studied InAs nanowires on different substrates. We have also investigated interactions between wires and with gold features patterned onto the substrates.

    Download full text (pdf)
    fulltext
  • 29.
    Conache, Gabriela
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Gray, Struan M.
    Avd. f. Fasta Tillståndets Fysik, Lunds Universitet, Sweden.
    Ribayrol, Aline
    Avd. f. Fasta Tillståndets Fysik, Lunds Universitet, Sweden.
    Fröberg, Linus
    Avd. f. Fasta Tillståndets Fysik, Lunds Universitet, Sweden.
    Samuelson, Lars
    Avd. f. Fasta Tillståndets Fysik, Lunds Universitet, Sweden.
    Montelius, Lars
    Avd. f. Fasta Tillståndets Fysik, Lunds Universitet, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Comparative friction measurements of InAs nanowires on three substrates2010In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 108, no 9, p. 094307-094307-5Article in journal (Refereed)
    Abstract [en]

    We have investigated friction between InAs nanowires and three different substrates: SiO2, fluorosilanized SiO2, and Si3N4. The nanowires were pushed laterally with the tip of an atomic force microscope and the friction force per unit length for both static and sliding friction was deduced from the equilibrium shape of the bent wires. On all three substrates, thick wires showed a difference between sliding and static friction of up to three orders of magnitude. Furthermore, all substrates display a transition to stick-slip motion for nanowires with a diameter of less than about 40 nm. Hydrophobic and hydrophilic substrates display similar friction behavior suggesting that a condensed water layer does not strongly influence our results. The patterns and trends in the friction data are similar for all three substrates, which indicates that they are more fundamental in character and not specific to a single substrate. ©2010 American Institute of Physics.

  • 30.
    Conache, Gabriela
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Lund University, Solid State Physics/Nanometer Consortium, Box 118, S-221 00, Lund, Sweden.
    Gray, Struan M.
    Lund University, Solid State Physics/Nanometer Consortium, Box 118, S-221 00, Lund, Sweden.
    Ribayrol, Aline
    Lund University, Solid State Physics/Nanometer Consortium, Box 118, S-221 00, Lund, Sweden.
    Fröberg, Linus
    Lund University, Solid State Physics/Nanometer Consortium, Box 118, S-221 00, Lund, Sweden.
    Samuelson, Lars
    Lund University, Solid State Physics/Nanometer Consortium, Box 118, S-221 00, Lund, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Montelius, Lars
    Lund University, Solid State Physics/Nanometer Consortium, Box 118, S-221 00, Lund, Sweden.
    Nanowire friction with an applied bias2009Conference paper (Refereed)
    Abstract [en]

    Recently, we have shown how the friction acting on nanowires pushed across a surface by an AFM tip can be determined by measuring the radius of curvature of the bent wire aŸer manipulation. This technique allows us to study the friction properties of an extended mesoscale contact. Our main focus has been to determine whether such contacts behave like macroscopic objects, in which dišerences between the 'true' and 'apparent' contact areas play a key role and friction varies linearly with the applied normal force, or whether they are more like atomic-scale point contacts, wheremore fundamental processes dominate and friction oŸen is independent of the normal force. In this work we show how the friction between InAs nanowires and an insulating silicon nitride layer on a conductive silicon substrate varies when a DC voltage is applied to the AFM tip during manipulation. e tip charges the capacitor formed by the wire and the grounded silicon back contact, giving rise to attractive Coulomb forces and thus increasing the contact pressure between the wire and the silicon nitride. In this way we can vary the normal force on the sliding surfaces using a single wire, with a constant structure and contact geometry. Using nanowires of about 40-50 nm diameter and a few microns in length we have applied tip voltages in the range +12 to -12 V. Simplemodeling indicates that these voltages su›ce to give similar levels of band-lling and depletion to when the same wires are used in working wrap-gate or back-gate devices. A monotonic increase of the sliding friction with the voltage applied on the tip was observed. is implies that the friction increases with the normal force and that this mesoscopic system behaves more like a macroscopic contact, despite the nanometer size of the contact in the direction of motion.

  • 31.
    Conache, Gabriela
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Ribayrol, Aline
    Avd. f. Fasta Tillståndets Fysik, Lunds Universitet, Sweden.
    Fröberg, Linus
    Avd. f. Fasta Tillståndets Fysik, Lunds Universitet, Sweden.
    Borgström, Magnus T.
    Avd. f. Fasta Tillståndets Fysik, Lunds Universitet, Sweden.
    Samuelson, Lars
    Avd. f. Fasta Tillståndets Fysik, Lunds Universitet, Sweden.
    Montelius, Lars
    Avd. f. Fasta Tillståndets Fysik, Lunds Universitet, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Gray, Struan M.
    Avd. f. Fasta Tillståndets Fysik, Lunds Universitet, Sweden.
    Bias-controlled friction of InAs nanowires on a silicon nitride layer studied by atomic force microscopy2010In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 82, no 3Article in journal (Refereed)
    Abstract [en]

    By studying how nanowires lying on a surface bend when pushed by an atomic force microscopy tip we are able to measure the friction between them and the substrate. Here, we show how the friction between InAs nanowires and an insulating silicon nitride layer varies when a dc voltage is applied to the tip during manipulation. The bias charges the capacitor formed by the wire and the grounded silicon back contact. Electrostatic forces increase the contact pressure and allow us to tune the friction between the wire and the silicon nitride surface. Using nanowires of about 40-70 nm diameter and a few microns in length we have applied biases in the range +12 to -12 V. A monotonic increase of the sliding friction with voltage was observed. This increase in friction with the normal force implies that the mesoscopic nanowire-surface system behaves like a macroscopic contact, despite the nanometer size of the contact in the direction of motion. The demonstrated bias-controlled friction has potential applications in MEMS/NEMS devices.

  • 32.
    Demin, Mikhail
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Finite Volume Methods for Option Pricing2011Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
    Download full text (pdf)
    micdem_thesis
  • 33.
    Diao, Zhu
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Sauer, Vincent T. K.
    National Institute for Nanotechnology, Alberta, Canada; Department of Biological Sciences & Department of Electrical and Computer Engineering, University of Alberta, Alberta, Canada.
    Hiebert, Wayne K.
    National Institute for Nanotechnology, Alberta, Canada & Department of Physics, University of Alberta, Alberta, Canada.
    Integrated On-Chip Nano-Optomechanical Systems2017In: International Journal of High Speed Electronics and Systems, ISSN 0129-1564, Vol. 26, no 1-2, article id 1740005Article in journal (Refereed)
    Abstract [en]

    Recent developments in integrated on-chip nano-optomechanical systems are reviewed. Silicon-based nano-optomechanical devices are fabricated by a two-step process, where the first step is a foundry-enabled photonic circuits patterning and the second step involves in-house mechanical device release. We show theoretically that the enhanced responsivity of near-field optical transduction of mechanical displacement in on-chip nano-optomechanical systems originates from the finesse of the optical cavity to which the mechanical device couples. An enhancement in responsivity of more than two orders of magnitude has been observed when compared side-by-side with free-space interferometry readout. We further demonstrate two approaches to facilitate large-scale device integration, namely, wavelength-division multiplexing and frequency-division multiplexing. They are capable of significantly simplifying the design complexity for addressing individual nano-optomechanical devices embedded in a large array. © 2017 World Scientific Publishing Company.

  • 34.
    Dzharayan, Gayk
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Voronova, Elena
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Pricing of exotic options under the Kou model by using the Laplace transform2011Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this thesis we present the Laplace transform method of option pricing and it's realization, also compare it with another methods. We consider vanilla and exotic options, but more attention we pay to the two-asset correlation options. We chose the one of the modifications of Black-Scholes model, the Kou double exponential jump-diffusion model with the double exponential distribution of jumps, as model of the underlying stock prices development. The computations was done by the Laplace transform and it's inversion by the Euler method. We will present in details proof of finding Laplace transforms of put and call two-asset correlation options, the calculations of the moment generation function of the jump-diffusion by Levy-Khintchine formulae in cases without jumps and with independent jumps, and direct calculation of the risk-neutral expectation by solving double integral. Our work also contains the programme code for two-asset correlation call and put options. We will show the realization of our programme in the real data. As a result we see how our model complies on the NASDAQ OMX Stock-holm Market, considering the two-asset correlation options on three cases by stock prices of Handelsbanken, Ericsson and index OMXS30.

    Download full text (pdf)
    fulltext
  • 35.
    Ernst, Robert
    et al.
    Halmstad University, School of Information Technology.
    Nilsson, Emil
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Viberg, Per-Arne
    Swedish Adrenaline AB, Halmstad, Sweden.
    60GHz Vital Sign Radar using 3D-printed Lens2016In: 2016 IEEE SENSORS, Piscataway: IEEE, 2016, article id 7808774Conference paper (Refereed)
    Abstract [en]

    There is an increased interest in contact-less vital sign monitoring methods as they offer higher flexibility to the individual being observed. Recent industrial development enabled radar functionality to be packed in single-chip solutions, decreasing application complexity and speeding up designs. Within this paper, a vital sign radar has been developed utilizing a recently released 60GHz frequency modulated continuous wave single-chip radar in combination with 3D-printed quasi-optics. The electronics development has been focused on compactness and high system integration using a low cost design process. The final experiments prove that the radar is capable of tracking human respiration rate and heartbeat at the same time from a distance of 1m.

  • 36.
    Friel, Ross
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Gerling-Gedin, Maria
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Nilsson, Emil
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Andreasson, Björn Pererik
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    3D Printed Radar Lenses with Anti-Reflective Structures2019In: Designs, E-ISSN 2411-9660, Vol. 3, no 2, article id 28Article in journal (Refereed)
    Abstract [en]

    Background: The purpose of this study was to determine if 3D printed lenses with wavelength specific anti-reflective (AR) surface structures would improve beam intensity and thus radar efficiency for a Printed Circuit Board (PCB)-based 60 GHz radar. This would have potential for improved low-cost radar lenses for the consumer product market. Methods: A hyperbolic lens was designed in 3D Computer Aided Design (CAD) software and was then modified with a wavelength specified AR structure. Electromagnetic computer simulation was performed on both the ‘smooth’ and ‘AR structure’ lenses and compared to actual 60 GHz radar measurements of 3D printed polylactic acid (PLA) lenses. Results: The simulation results showed an increase of 10% in signal intensity of the AR structure lens over the smooth lens. Actual measurement showed an 8% increase in signal of the AR structure lens over the smooth lens. Conclusions: Low cost and readily available Fused Filament Fabrication (FFF) 3D printing has been shown to be capable of printing an AR structure coated hyperbolic lens for millimeter wavelength radar applications. These 3D Printed AR structure lenses are effective in improving radar measurements over non-AR structure lenses. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.

    Download full text (pdf)
    3D Printed Radar Lenses
  • 37.
    Gooth, Johannes
    et al.
    Institute of Nanostructure and Solid State Physics, Universität Hamburg, Hamburg, Germany & IBM Research-Zurich, Rüschlikon, Switzerland.
    Zierold, Robert
    Institute of Nanostructure and Solid State Physics, Universität Hamburg, Hamburg, Germany.
    Sergelius, Philip
    Institute of Nanostructure and Solid State Physics, Universität Hamburg, Hamburg, Germany.
    Hamdou, Bacel
    Institute of Nanostructure and Solid State Physics, Universität Hamburg, Hamburg, Germany.
    Garcia, Javier
    Institute for Metallic Materials, IFW Dresden, Dresden, Germany.
    Damm, Christine
    Institute for Metallic Materials, IFW Dresden, Dresden, Germany.
    Rellinghaus, Bernd
    Institute for Metallic Materials, IFW Dresden, Dresden, Germany.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Division of Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Pertsova, Anna
    Department of Physics and Electrical Engineering, Linnaeus University, Kalmar, Sweden.
    Canali, Carlo
    Department of Physics and Electrical Engineering, Linnaeus University, Kalmar, Sweden.
    Borg, Mattias
    IBM Research-Zurich, Rüschlikon, Switzerland.
    Nielsch, Kornelius
    Institute of Nanostructure and Solid State Physics, Universität Hamburg, Hamburg, Germany & Institute for Metallic Materials, IFW Dresden, Dresden, Germany.
    Local Magnetic Suppression of Topological Surface States in Bi2Te3 Nanowires2016In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 10, no 7, p. 7180-7188Article in journal (Refereed)
    Abstract [en]

    Locally induced, magnetic order on the surface of a topological insulator nanowire could enable room-temperature topological quantum devices. Here we report on the realization of selective magnetic control over topological surface states on a single facet of a rectangular Bi2Te3 nanowire via a magnetic insulating Fe3O4 substrate. Low-temperature magnetotransport studies provide evidence for local time-reversal symmetry breaking and for enhanced gapping of the interfacial 1D energy spectrum by perpendicular magnetic-field components, leaving the remaining nanowire facets unaffected. Our results open up great opportunities for development of dissipation-less electronics and spintronics. © 2016 American Chemical Society.

  • 38.
    Guarese, Renan
    et al.
    Institute of Informatics, Federal University of Rio Grande Do sul, Porto Alegre, Brazil.
    Nilsson, Emil
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Andreasson, Björn Pererik
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    MacIel, Anderson
    Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
    A proposal for augmented situated visualization towards EMC testing2020In: CEUR Workshop Proceedings / [ed] Moser T.; Bruckner F., CEUR-WS , 2020, Vol. 2618, p. 12-15Conference paper (Refereed)
    Abstract [en]

    Copyright © 2020 for this paper by its authors.In EMC testing, 3D electromagnetic field data often needs to be visually analysed by an expert in order to detect product defects or unwanted interference between multiple devices. In this sense, the present work proposes the use of data visualization techniques allied to an Augmented Reality user interface to provide information that helps professionals to analyse the same data, however spatially situated where it was first measured. Apart from visualizing it, users may also interact with the data to narrow down their search by switching the attributes being displayed, combining them together, applying filters or changing the formatting in which data is presented. The approaches being proposed in this work will ultimately be tested against each other in comparable 2D and 3D interactive visualizations of the same data in a series of usability assessments with users to validate the solutions. The goal is to ultimately expose whether AR can help users to make more accurate decisions, particularly in EMC related tasks.

  • 39.
    Guo, Matilda
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE). Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Lapenkova, Maria
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE). Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Numerical Methods for Pricing Swing Options in the Electricity Market2010Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Since the liberalisation of the energy market in Europe in the early 1990s, much opportunity to trade electricity as a commodity has arisen. One significant consequence of this movement is that market prices have become more volatile instead of its tradition constant rate of supply. Spot price markets have also been introduced, affecting the demand of electricity as companies now have the option to not only produce their own supply but also purchase this commodity from the market. Following the liberalisation of the energy market, hence creating a greater demand for trading of electricity and other types of energy, various types of options related to the sales, storage and transmission of electricity have consequently been introduced.

    Particularly, swing options are popular in the electricity market. As we know, swing-type derivatives are given in various forms and are mainly traded as over-the-counter (OTC) contracts at energy exchanges. These options offer flexibility with respect to timing and quantity.

    Traditionally, the Geometric Brownian Motion (GBM) model is a very popular and standard approach for modelling the risk neutral price dynamics of underlyings. However, a limitation of this model is that it has very few degrees of freedom, as it does not capture the complex behaviour of electricity prices. In short the GBM model is inefficient in the pricing of options involving electricity. Other models have subsequently been used to bridge this inadequacy, e.g. spot price models, futures price models, etc.

    To model risk-neutral commodity prices, there are basically two different methodologies, namely spot and futures or so-called term structure models. As swing options are usually written on spot prices, by which we mean the current price at which a particular commodity can be bought or sold at a specified time and place, it is important for us to examine these models in order to more accurately inculcate their effect on the pricing of swing options.

    Monte Carlo simulation is also a widely used approach for the pricing of swing options in the electricity market. Theoretically, Monte Carlo valuation relies on risk neutral valuation and the technique used is to simulate as many (random) price paths of the underlying(s) as possible, and then to average the calculated payoff for each path, discounted to today's prices, giving the value of the desired derivative. Monte Carlo methods are particularly useful in the valuation of derivatives with multiple sources of uncertainty or complicated features, like our electricity swing options in question. However, they are generally too slow to be considered a competitive form of valuation, if any analytical techniques of valuation exist. In other words, the Monte Carlo approach is, in a sense, a method of last resort.

    In this thesis, we aim to examine a numerical method involved in the pricing of swing options in the electricity market. We will consider an existing and widely accepted electricity price process model, use the finite volume method to formulate a numerical scheme in order to calibrate the prices of swing options and make a comparison with numerical solutions obtained using the theta-scheme. Further contributions of this thesis include a comparison of results and also a brief discussion of other possible methods.

    Download full text (pdf)
    FULLTEXT02
  • 40.
    Gåård, Anders
    et al.
    Karlstads Universitet, Karlstad, Sverige.
    Löfgren, Hans
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Nilsson, Bertil
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Hallbäck, Nils
    Karlstads Universitet, Karlstad, Sverige.
    Införandet av Computer Based Mathematics (CBM) i ingenjörsutbildningar2017Conference paper (Other (popular science, discussion, etc.))
    Abstract [sv]

    CBM är ett koncept som innebär användning av datorn och matematikprogramvaror som huvudverktyg i under-visningen. Istället för att som i traditionell undervisning kombinera handräkning med datorlabbar ligger tyngdpunkten i en CBM-kurs på datoriserade beräkningsverktyg. Härav för-flyttas fokus mot konceptförtåelse, modellering och tolkning av resultat. Vid Högskolan i Halmstad och Karlstads Universitet finns idag flera kurser baserat på CBM. Kvantitativt har införandet lett till ökad studentgenomströmning samtidigt som innehållet i kurser har ökat. Kvalitativa markörer, såsom studentens egen uppfattning om konceptuell förståelse och nyfikenhet inom ämnet, har baserat på kursvärderingar också ökat. 

    Download full text (pdf)
    fulltext
  • 41.
    Hussain, Laiq
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Wang, Q.
    Acreo Swedish ICT AB, Kista, Sweden.
    Karim, A.
    Acreo Swedish ICT AB, Kista, Sweden.
    Anderson, J.
    Acreo Swedish ICT AB, Kista, Sweden.
    Jafari, Mehrdad
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Song, J.
    Center for Opto-Electronic Convergence Systems, Korea Institute of Science and Technology, Seoul, South Korea.
    Choi, W. J.
    Center for Opto-Electronic Convergence Systems, Korea Institute of Science and Technology, Seoul, South Korea.
    Han, I. K.
    Center for Opto-Electronic Convergence Systems, Korea Institute of Science and Technology, Seoul, South Korea.
    Lim, J. Y.
    Center for Opto-Electronic Convergence Systems, Korea Institute of Science and Technology, Seoul, South Korea.
    SWIR-LWIR Photoluminescence from Sb-based Epilayers Grown on GaAs Substrates by using MBE2018In: Journal of the Korean Physical Society, ISSN 0374-4884, E-ISSN 1976-8524, Vol. 73, no 11, p. 1604-1611Article in journal (Refereed)
    Abstract [en]

    Utilizing Sb-based bulk epilayers on large-scale low-cost substrates such as GaAs for fabricating infrared (IR) photodetectors is presently attracting significant attention worldwide. For this study, three sample series of GaAsxSb1−x, In1−xGaxSb, and InAsxSb1x with different compositions were grown on semi-insulating GaAs substrates by using molecular beam epitaxy (MBE) and appropriate InAs quantum dots (QDs) as a defect-reduction buffer layer. Photoluminescence (PL) signals from these samples were observed over a wide IR wavelength range from 2 μm to 12 μm in agreement with the expected bandgap, including bowing effects. In particular, interband PL signals from InAsxSb1−x and In1−xGaxSb samples even at room temperature show promising potential for IR photodetector applications.

    Download full text (pdf)
    fulltext
  • 42.
    Höglund, Linda
    et al.
    Acreo AB, Kista, Sweden.
    Holtz, Per-Olof
    Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden.
    Asplund, Carl
    IRnova, Kista, Sweden.
    Wang, Qin
    Acreo AB, Kista, Sweden.
    Almqvist, Susanne
    Acreo AB, Kista, Sweden.
    Malm, Hedda
    IRnova, Kista, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Andersson, Jan Yngve
    Acreo AB, Kista, Sweden.
    Dual source optical pumping experiments revealing the origin of low temperature photocurrent peaks in quantum dots-in-a-well infrared photodetectors2008Conference paper (Refereed)
  • 43.
    Höglund, Linda
    et al.
    Acreo AB, Kista, Sweden & Linköping University, Linköping, Sweden.
    Holtz, Per-Olof
    Linköping University, Linköping, Sweden.
    Asplund, Carl
    IRnova, Kista, Sweden.
    Wang, Qin
    Acreo AB, Kista, Sweden.
    Almqvist, Susanne
    Acreo AB, Kista, Sweden.
    Petrini, Erik
    Acreo AB, Kista, Sweden.
    Andersson, Jan Y.
    Acreo AB, Kista, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Lund University, Lund, Sweden.
    Tuning of the detection wavelength in quantum dots-in-a-well infrared photodetectors2008In: Proceedings of SPIE, 6940, Infrared Technology and Applications XXXIV, 694002, 2008, Vol. 6940, no 1-2, article id 694002Conference paper (Refereed)
    Abstract [en]

    In this study, bias mediated tuning of the detection wavelength within the infrared wavelength region is demonstrated for quantum dots-in-a-well (DWELL) infrared photodetectors. In DWELL structures, intersubband transitions in the conduction band occur from a discrete state in the quantum dot to a subband inthe quantum well. Compared to "conventional" quantum dot infrared photodetectors, where the transitions take place between different discrete bands in thequantum dots, new possibilities to tune the detection wavelength window are opened up, partly by varying the quantum dot energy levels and partly by adjusting the width and composition of the quantum well. In the DWELL structure used, an asymmetric positioning of the InAs quantum dot layer in a 8 nm wide In0.15Ga0.85As/GaAs QW has been applied which enables tuning of the peak detection wavelength within the long wavelength infrared (LWIR; 8 - 14 gm) region. When the applied bias was reversed, a wavelength shift from 8.5 to 9.5 mu m was observed for the peak position in the spectral response. For another DWELL structure, with a well width of 2 nm, the tuning range of the detector could be shifted from the medium wavelength infrared (MWIR; 3-5 mu m) region to the LWIR region. With small changes in the applied bias, the peak detection wavelength could be shifted from 5.1 to 8 mu m. These tuning properties ofDWELL structures could be essential for applications such as modulators and two-colour infrared detection. © (2008) COPYRIGHT SPIE--The International Society for Optical Engineering.

  • 44.
    Höglund, Linda
    et al.
    Acreo AB, Kista, Sweden.
    Holtz, Per-Olof
    IFM, Linköping University, Linköping, Sweden.
    Asplund, Carl
    IRnova AB, Kista, Sweden.
    Wang, Qin
    Acreo AB, Kista, Sweden.
    Almqvist, Susanne
    Acreo AB, Kista, Sweden.
    Petrini, Erik
    Acreo AB, Kista, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Andersson, Jan Y.
    Acreo AB, Kista, Sweden.
    Voltage mediated tuning of the detection wavelength in quantum dots-in-a-well infrared photodetectors2008Conference paper (Refereed)
  • 45.
    Höglund, Linda
    et al.
    Industrial Nano- and Microtechnology, Acreo AB, Kista, Sweden.
    Holtz, Per-Olof
    Department of Physics, Chemistry and Biology (LFM), Linköping University, Linköping, Sweden.
    Ouattara, L.
    Synchrotron Radiation Research, Lund University, Lund, Sweden.
    Asplund, Carl
    IRnova, Kista, Sweden.
    Wang, Qin
    Industrial Nano- and Microtechnology, Acreo AB, Kista, Sweden.
    Almqvist, Susanne
    Industrial Nano- and Microtechnology, Acreo AB, Kista, Sweden.
    Petrini, Erik
    Industrial Nano- and Microtechnology, Acreo AB, Kista, Sweden.
    Malm, Hedda
    IRnova, Kista, Sweden.
    Borglind, J.
    Industrial Nano- and Microtechnology, Acreo AB, Kista, Sweden.
    Smuk, S.
    Industrial Nano- and Microtechnology, Acreo AB, Kista, Sweden.
    Mikkelsen, A.
    Synchrotron Radiation Research, Lund University, Lund, Sweden.
    Lundgren, E.
    Synchrotron Radiation Research, Lund University, Lund, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Solid State Physics and the Nanometer Consortium, Lund University, Lund, Sweden.
    Andersson, Jan Y.
    Industrial Nano- and Microtechnology, Acreo AB, Kista, Sweden.
    Quantum dots-in-a-well infrared photodetectors for long wavelength infrared detection2006In: Proceedings of SPIE: The International Society for Optical Engineering / [ed] James G. Grate, Francois Kajzar & Mikael lindgren, Bellingham, Wash.: SPIE - International Society for Optical Engineering, 2006, p. U51-U63Conference paper (Refereed)
    Abstract [en]

    We report on a quantum dots-in-a-well infrared photodetector (DWELL QDIP) grown by metal organic vapor phase epitaxy. The DWELL QDIP consisted of ten stacked InAs/In0.5Ga0.85As/GaAs QD layers embedded between n-doped contact layers. The density of the QDs was about 9 × 10 10 cm-2 per QD layer. The energy level structure of the DWELL was revealed by optical measurements of interband transitions, and from a comparison with this energy level scheme the origin of the photocurrent peaks could be identified. The main intersubband transition contributing to the photocurrent was associated with the quantum dot ground state to the quantum well excited state transition. The performance of the DWELL QDIPs was evaluated regarding responsivity and dark current for temperatures between 15 K and 77 K. The photocurrent spectrum was dominated by a LWIR peak, with a peak wavelength at 8.4 μm and a full width at half maximum (FWHM) of 1.1 μm. At an operating temperature of 65 K, the peak responsivity was 30 mA/W at an applied bias of 4 V and the dark current was 1.2×10-5 A/cm2. Wavelength tuning from 8.4 μm to 9.5 μm was demonstrated, by reversing the bias of the detector.

  • 46.
    Höglund, Linda
    et al.
    Acreo AB.
    Holtz, Per-Olof
    IFM, Linköping University.
    Pettersson, Håkan
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Asplund, Carl
    IRnova.
    Wang, Qin
    Acreo AB.
    Almqvist, Susanne
    Acreo AB.
    Malm, Hedda
    IRnova.
    Petrini, Erik
    Acreo AB.
    Andersson, Jan
    Acreo AB.
    Selective optical doping to predict the performance and reveal the origin of photocurrent peaks in quantum dots-in-a-well infrared photodetectors2009In: Infrared physics & technology, ISSN 1350-4495, E-ISSN 1879-0275, Vol. 52, no 6, p. 272-275Article in journal (Refereed)
    Abstract [en]

    Resonant optical pumping across the band gap was used as artificial doping in InAs/In0.15Ga0.85As/GaAs quantum dots-in-a-well infrared photodetectors. Through efficient filling of the quantum dot energy levels by simultaneous optical pumping into the ground states and the excited states of the quantum dots, the response was increased by a factor of 10. Low temperature photocurrent peaks observed at 120 and 148 meV were identified as intersubband transitions emanating from the quantum dot ground state and the quantum dot excited state, respectively by a selective increase of the electron population in the different quantum dot energy levels.

  • 47.
    Höglund, Linda
    et al.
    Acreo AB.
    Karlsson, Fredrik
    IFM, Linköping University.
    Holtz, Per-Olof
    IFM, Linköping University.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Pistol, Mats-Erik
    Avd. f. Fasta Tillståndets Fysik, Lunds Universitet.
    Wang, Qin
    Acreo AB.
    Almqvist, Susanne
    Acreo AB.
    Asplund, Carl
    IRnova.
    Malm, Hedda
    IRnova.
    Petrini, Erik
    Acreo AB.
    Andersson, Jan
    Acreo AB.
    Energy level scheme of InAs/InxGa1-xAs/GaAs quantum-dots-in-a-well infrared photodetector structures2010In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 82, no 3, p. 035314-Article in journal (Refereed)
    Abstract [en]

    A thorough investigation of quantum-dots-in-a-well structures for infrared photodetector applications has been performed employing different experimental techniques. The electronic structure of self-assembled InAs quantum dots embedded in an In0.15Ga0.85As/GaAs quantum well (QW) was deduced from photoluminescence (PL) and PL excitation (PLE) spectroscopy. From polarization-dependent PL it was revealed that the quantum dots hold two electron energy levels and two heavy-hole levels. Tunnel capacitance spectroscopy confirmed an electron energy level separation of about 50 meV, and additionally, that the conduction-band ground state and excited state of the dots are twofold and fourfold degenerates, respectively. Intersubband photocurrent spectroscopy, combined with simultaneous interband pumping of the dots, revealed a dominant transition at 150 meV (8.5 mu m) between the ground state of the quantum dots and the excited state of the QW. Results from detailed full three-dimensional calculations of the electronic structure, including effects of composition intermixing and interdot interactions, confirm the experimentally unravelled energy level scheme of the dots and well.

    Download full text (pdf)
    fulltext
  • 48.
    Jafari Jam, Reza
    et al.
    Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    Heurlin, Magnus
    Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    Jain, Vishal
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS). Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    Kvennefors, Anders
    Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    Graczyk, Mariusz
    Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    Maximov, Ivan
    Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    Borgström, Magnus T.
    Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    Samuelson, Lars
    Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    III-V nanowire synthesis by use of electrodeposited gold particles2015In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 15, no 1, p. 134-138Article in journal (Refereed)
    Abstract [en]

    Semiconductor nanowires are great candidates for building novel electronic devices. Considering the cost of fabricating such devices, substrate reuse and gold consumption are the main concerns. Here we report on implementation of high throughput gold electrodeposition for selective deposition of metal seed particles in arrays defined by lithography for nanowire synthesis. By use of this method, a reduction in gold consumption by a factor of at least 300 was achieved, as compared to conventional thermal evaporation for the same pattern. Because this method also facilitates substrate reuse, a significantly reduced cost of the final device is expected. We investigate the morphology, crystallography, and optical properties of InP and GaAs nanowires grown from electrodeposited gold seed particles and compare them with the properties of nanowires grown from seed particles defined by thermal evaporation of gold. We find that nanowire synthesis, as well as the material properties of the grown nanowires are comparable and quite independent of the gold deposition technique. On the basis of these results, electrodeposition is proposed as a key technology for large-scale fabrication of nanowire-based devices.

  • 49.
    Jafari Jam, Reza
    et al.
    Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    Heurlin, Magnus
    Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    Kvennefors, Anders
    Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    Graczyk, Mariusz
    Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    Jain, Vishal
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    Borgström, Magnus T.
    Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    Samuelson, Lars
    Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    Maximov, Ivan
    Division of Solid State Physics/Nanometer Structure Consortium, Lund University, Lund, Sweden.
    Nanoimprint Lithography and Gold Electroplating for Nanowire Seed Particle Definition2013Conference paper (Refereed)
  • 50.
    Jain, Vishal
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Heurlin, Magnus
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Barrigon, Enrique
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Bosco, Lorenzo
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Nowzari, Ali
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Schroff, Shishi
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Boix, Virginia
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Karimi, Mohammad
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Jafari Jam, Reza
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Berg, Alexander
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Samuelson, Lars
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Borgström, Magnus T.
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Capasso, Federico
    School of Engineering and Applied Sciences, Harvard University, Cambridge, United States.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    InP/InAsP Nanowire-Based Spatially Separate Absorption and Multiplication Avalanche Photodetectors2017In: ACS Photonics, E-ISSN 2330-4022, Vol. 4, no 11, p. 2693-2698Article in journal (Refereed)
    Abstract [en]

    Avalanche photodetectors (APDs) are key components in optical communication systems due to their increased photocurrent gain and short response time as compared to conventional photodetectors. A detector design where the multiplication region is implemented in a large band gap material is desired to avoid detrimental Zener tunneling leakage currents, a concern otherwise in smaller band gap materials required for absorption at 1.3/1.55 μm. Self-assembled III-V semiconductor nanowires offer key advantages such as enhanced absorption due to optical resonance effects, strain-relaxed heterostructures, and compatibility with mainstream silicon technology. Here, we present electrical and optical characteristics of single InP and InP/InAsP nanowire APD structures. Temperature-dependent breakdown characteristics of p+-n-n+ InP nanowire devices were investigated first. A clear trap-induced shift in breakdown voltage was inferred from I-V measurements. An improved contact formation to the p+-InP segment was observed upon annealing, and its effect on breakdown characteristics was investigated. The band gap in the absorption region was subsequently varied from pure InP to InAsP to realize spatially separate absorption and multiplication APDs in heterostructure nanowires. In contrast to the homojunction APDs, no trap-induced shifts were observed for the heterostructure APDs. A gain of 12 was demonstrated for selective optical excitation of the InAsP segment. Additional electron-beam-induced current measurements were carried out to investigate the effect of local excitation along the nanowire on the I-V characteristics. Simulated band profiles and electric field distributions support our interpretation of the experiments. Our results provide important insight for optimization of avalanche photodetector devices based on III-V nanowires. © 2017 American Chemical Society

    Download full text (pdf)
    fulltext
123 1 - 50 of 131
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf