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Semiconductor nanostructures enabled by aerosol technology

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Frontiers of physics 2014年第3期9卷 398-418页

作者： Martin H. magnusson B. Jonas Ohlsson Mikael T. Bjork Kimberly A. Dick magnus T. Borgstrom Knut Deppert Lars Samuelson Solid State Physics Lund University Box 118 SE-22100 Lund Sweden Sol Voltaics AB Ideon Science Park Scheelevagen 17 SE-22370 Lund Sweden QuNano AB Ideon Science Park Scheelevaigen 17 SE-22370 Lund Sweden Center for Analysis and Synthesis Lund University Box 124 SE-22100 Lund Sweden

Aerosol technology provides efficient methods for producing nanoparticles with well-controlled composition and size distribution. This review provides an overview of methods and results obtained by using aerosol technology for producing nanostruetures for a variety of applications in semiconductor physics and device technology. Examples are given from： production of metal and metal alloy particles： semiconductor nanoparticles; semiconductor nanowires, grown both in the aerosol phase and on substrates; physics studies based on individual aerosol-generated devices; and large area deviees based on aerosol particles.

关键词： aerosol nanoparticle nanowire metal-organic vapor phase epitaxy (MOVPE) device physics light emitting diodes (LED) solar cell

Phases of Stable Representations of Euclidean and Wild Quivers

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Algebra Colloquium 2024年第3期31卷 505-524页

作者： magnus Engenhorst Deutsche Postbank AG Bundeskanzlerplatz 6Bonn 53113Germany

We consider stable representations of non-Dynkin quivers with respect to a central *** attract a lot of interest in mathematics and physics since they can be identified with so-called BPS *** motivation is the work of Dimitrov et *** the phases of stable representations of the generalized Kronecker *** aim is to explain for general Euclidean and wild quivers the behavior of phases of stable representations well known in some *** addition,we study especially the behavior of preinjective,postprojective and regular indecomposable *** show that the existence of a stable representation with self-extensions implies the existence of infinitely many stables without self-extensions for rigid central *** this case the phases of the stable representations approach one or two limit *** particular,the phases are not dense in two *** category of representations of acyclic quivers is a special case of rigid Abelian categories which show this behavior for rigid central charges.

关键词： stable representation Euclidean quiver wild quiver Abelian category triangulated category

InP/GaInP nanowire tunnel diodes

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Nano Research 2018年第5期11卷 2523-2531页

作者： Xulu Zeng Gaute Otnes magnus Heurlin Renato T Mourao magnus T Borgstrom Solid State Physics NanoLund Department of Physics Lund University P.O. Box 118 Lund 5E-22100 Sweden Instituto de Fisica Universidade Federal do Rio de Janeiro Caixa Postal 68528 Rio de Janeiro 21941-972 Brazil

Semiconductor nanowire （NW） solar cells with a single p-n junction have exhibited efficiency comparable to that of their planar counterparts with a substantial reduction in material consumption. Tandem geometry is a path toward the fabrication of devices with even higher efficiencies, for which a key step is the fabrication of tunnel （Esaki） diodes within NWs with the correct diameter, pitch, and material combination for maximized efficiency. InP/GaInP and GaInP/InP NW tunnel diodes with band gap combinations corresponding to high-efficiency solar energy harvesting were fabricated and their electrical characteristics and material properties were compared. Four different configurations, with respect to material composition and doping, were investigated. The NW arrays were grown with metal-organic vapor-phase epitaxy from Au particles by use of nano-imprint lithography, metal evaporation and lift-off. Electrical measurements showed that the NWs behave as tunnel diodes in both InP （bottom）/GaInP （top） and GaInP （bottom）/InP （top） configurations, exhibiting a maximum peak current density of 25 A/cm^2, and maximum peak to valley current ratio of 2.5 at room temperature. The realization of NW tunnel diodes in both InP/GaInP and GaInP/InP configurations represent an opportunity for the use of NW tandem solar cells, whose efficiency is independent of the growth order of the different materials, increasing the flexibility regarding dopant incorporation polarity.

关键词： nanowire tunnel diode InP GaInP tandem junction solar cell

Laparoscopic revolution in bariatric surgery

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World Journal of Gastroenterology 2014年第41期20卷 15135-15143页

作者： magnus Sundbom Department of Surgical Sciences Uppsala University

The history of bariatric surgery is investigational. Dedicated surgeons have continuously sought for an ideal procedure to relieve morbidly obese patients from their burden of comorbid conditions, reduced life expectancy and low quality of life. The ideal procedure must have low complication risk, both in short- and long term, as well as minimal impact on daily life. The revolution of laparoscopic techniques in bariatric surgery is described in this summary. Advances in minimal invasive techniques have contributed to reduced operative time, length of stay, and complications. The development in bariatric surgery has been exceptional, resulting in a dramatic increase of the number of procedures performed world wide during the last decades. Although, a complex bariatric procedure can be performed with operative mortality no greater than cholecystectomy, specific procedure-related complications and other drawbacks must be taken into account. The evolution of laparoscopy will be the legacy of the 21st century and at present, day-care surgery and further reduction of the operative trauma is in focus. The impressive effects on comorbid conditions have prompted the adoption of minimal invasive bariatric procedures into the field of metabolic surgery.

关键词： Laparoscopy Bariatric surgery Minimal invasive surgery Gastric bypass Duodenal switch Gastric banding Metabolic surgery

Use of Microwave Radiances from Metop-C and Fengyun-3 C/D Satellites for a Northern European Limited-area Data Assimilation System

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Advances in Atmospheric Sciences 2021年第8期38卷 1415-1428页

作者： magnus LINDSKOG Adam DYBBROE Roger RANDRIAMAMPIANINA Swedish Meteorological and Hydrological Institute Folkborgsvägen 1760361 NorrköpingSweden Norwegian Meteorological Institute Henrik Mohns Plass 10371 OsloNorway

MetCoOp is a Nordic collaboration on operational Numerical Weather Prediction based on a common limited-area km-scale ensemble system. The initial states are produced using a 3-dimensional variational data assimilation scheme utilizing a large amount of observations from conventional in-situ measurements, weather radars, global navigation satellite system, advanced scatterometer data and satellite radiances from various satellite platforms. A version of the forecasting system which is aimed for future operations has been prepared for an enhanced assimilation of microwave radiances. This enhanced data assimilation system will use radiances from the Microwave Humidity Sounder, the Advanced Microwave Sounding Unit-A and the Micro-Wave Humidity Sounder-2 instruments on-board the Metop-C and Fengyun-3 C/D polar orbiting satellites. The implementation process includes channel selection, set-up of an adaptive bias correction procedure, and careful monitoring of data usage and quality control of observations. The benefit of the additional microwave observations in terms of data coverage and impact on analyses, as derived using the degree of freedom of signal approach, is demonstrated. A positive impact on forecast quality is shown, and the effect on the precipitation for a case study is examined. Finally, the role of enhanced data assimilation techniques and adaptions towards nowcasting are discussed.

关键词： data assimilation regional numerical weather prediction microwave radiances

Cheap and secure metatransactions on the blockchain using hash-based authorisation and preferred batchers

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Blockchain(Research and Applications) 2023年第2期4卷 41-66页

作者： William Hughes Tobias magnusson Alejandro Russo Gerardo Schneider Dept.of Computer Science and Engineering University of Gothenburg41296GothenburgSweden Dept.of Computer Science and Engineering Chalmers University41296GothenburgSweden

Smart contracts are self-executing programs running in the blockchain allowing for decentralised storage and execution without a ***-chain execution is expensive,with miners charging fees for distributed execution according to a cost model defined in the *** particular,transactions have a high fixed *** present MultiCall,a transaction-batching interpreter for Ethereum that reduces the cost of smart contract executions by gathering multiple users’transactions into a *** current implementation of MultiCall includes the following features:the ability to emulate Ethereum calls and create transactions,both from MultiCall itself and using an identity unique to the user;the ability to cheaply pay Ether to other MultiCall users;and the ability to authorise emulated transactions on behalf of multiple users in a single transaction using hash-based authorisation rather than more expensive *** improves upon a previous version of *** experiments show that MultiCall provides a saving between 57%and 99%of the fixed transaction cost compared with the standard approach of sending Ethereum transactions directly.

关键词： Ethereum Domain-specific language Interpreter Gas optimisation

Absorption of light in InP nanowire arrays

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Nano Research 2014年第6期7卷 816-823页

作者： Nicklas Anttu Alireza Abrand Damir Asoli magnus Heurlin Ingvar Aberg Lars Samuelson magnus Borgstrom Division of Solid State Physics and the Nanometer Structure Consortium at Lund University (nmC@LU) Lund University Box 118 Lund 22100 Sweden Sol Voltaics AB Ideon Science Park Scheelevagen 17 Lund 22370 Sweden

An understanding of the absorption of light is essential for efficient photovoltaic and photodetection applications with III-V nanowire arrays. Here, we correlate experiments with modeling and verify experimentally the predicted absorption of light in InP nanowire arrays for varying nanowire diameter and length. We find that 2,000 nm long nanowires in a pitch of 400 nm can absorb 94% of the incident light with energy above the band gap and, as a consequence, light which in a simple ray-optics description would be travelling between the nanowires can be efficiently absorbed by the nanowires. Our measurements demonstrate that the absorption for long nanowires is limited by insertion reflection losses when light is coupled from the air top-region into the array. These reflection losses can be reduced by introducing a smaller diameter to the nanowire-part closest to the air top-region. For nanowire arrays with such a nanowire morphology modulation, we find that the absorptance increases monotonously with increasing diameter of the rest of the nanowire.

关键词： indium phosphide semiconductor nanowire absorption of light

Sound Propagation Properties of the Discrete-Velocity Boltzmann Equation

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Communications in Computational Physics 2013年第3期13卷 671-684页

作者： Erlend magnus Viggen Department of Electronics and Telecommunications Norwegian University of Science and Technology(NTNU)7034 TrondheimNorway

As the numerical resolution is increased and the discretisation error decreases,the lattice Boltzmann method tends towards the discrete-velocity Boltzmann equation(DVBE).An expression for the propagation properties of plane sound waves is found for this *** expression is compared to similar ones from the NavierStokes and Burnett models,and is found to be closest to the *** anisotropy of sound propagation with the DVBE is examined using a two-dimensional velocity *** is found that both the anisotropy and the deviation between the models is negligible if the Knudsen number is less than 1 by at least an order of magnitude.

关键词： Lattice Boltzmann method discrete-velocity Boltzmann equation sound propagation computational aeroacoustics

Strategies to obtain pattern fidelity in nanowire growth from large-area surfaces patterned using nanoimprint lithography

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Nano Research 2016年第10期9卷 2852-2861页

作者： Gaute Otnes magnus Heurlin Mariusz Graczyk Jesper Wallentin Daniel Jacobsson Alexander Berg Ivan Maximov magnus T. Borgstrom Solid State Physics Lund University Box 118 S-22100 Lund Sweden

Position controlled nanowire growth is important for nanowire-based optoelectronic components which rely on light emission or light absorption. For solar energy harvesting applications, dense arrays of nanowires are needed; however, a major obstacle to obtaining dense nanowire arrays is seed particle displacement and coalescing during the annealing stage prior to nanowire growth. Here, we explore three different strategies to improve pattern preservation of large-area catalyst particle arrays defined by nanoimprint lithography for nanowire growth. First, we see that heat treating the growth substrate prior to nanoimprint lithography improves pattern preservation. Second, we explore the possibility of improving pattern preservation by fixing the seed particles in place prior to annealing by modifying the growth procedure. And third, we show that a SiNx growth mask can fully prevent seed particle displacement. We show how these strategies allow us to greatly improve the pattern fidelity of grown InP nanowire arrays with dimensions suitable for solar cell applications, ultimately achieving 100% pattern preservation over the sampled area. The generic nature of these strategies is supported through the synthesis of GaAs and GaP nanowires.

关键词： semiconductor nanowire nanoimprint lithography metal-organic vaporphase epitaxial (MOVPE) patterning