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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：纳米线阵列吸收率磷化铟反射损失光电探测光学器件区域耦合直径

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

Growth and optical properties of InxGa1-xP nanowires synthesized by selective-area epitaxy

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Nano Research 2017年第2期10卷 672-682页

作者： Alexander Berg Philippe Caroff Naeem Shahid Mark N. Lockrey Xiaoming Yuan magnus T. borgstrom Hark Hoe Tan Chennupati Jagadish Solid State Physics and NanoLund Lund University Box 118 SE-221 00 Lund Sweden Department of Electronic Materials Engineering Research School of Physics and Engineering The Australian National University Canberra ACT2601 Australia Australian National Fabrication Facility Research School of Physics and Engineering The Australian National University Canberra ACT 2601 Australia

Ternary III-V nanowires （NWs） cover a wide range of wavelengths in the solar spectrum and would greatly benefit from being synthesized as position-controlled arrays for improved vertical yield, reproducibility, and tunable optical absorption. Here, we report on successful selective-area epitaxy of metal-particle-free vertical InxGa1-xP NW arrays using metal-organic vapor phase epitaxy and detail their optical properties. A systematic growth study establishes the range of suitable growth parameters to obtain uniform NW growth over a large array. The optical properties of the NWs were characterized by room-temperature cathodoluminescence spectroscopy. Tunability of the emission wavelength from 870 nm to approximately 800 nm was achieved. Transmission electron microscopy and energy dispersive X-ray measurements performed on cross- section samples revealed a pure wurtzite crystal structure with very few stacking faults and a slight composition gradient along the NW growth axis.

关键词： nanowire InGaP selective-area epitaxy cathodoluminescence energy-dispersive X-ray spectroscopy

Large-energy-shift photon upconversion in degenerately doped InP nanowires by direct excitation into the electron gas

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Nano Research 2013年第10期6卷 752-757页

作者： Kilian Mergenthaler Azhar Iqbal Jesper Wallentin Sebastian Lehmann magnus T. borgstrom Lars Samuelson Arkady Yartsev Mats-Erik Pistol Solid State Physics/The Nanometer Structure Consortium Lund University P. O. Box 118 SE-22100 Lund Sweden Division of Chemical Physics Lund University P O. Box 118 SE-22100 Lund Sweden

Realizing photon upconversion in nanostructures is important for many next- generation applications such as biological labelling, infrared detectors and solar cells. In particular nanowires are attractive for optoelectronics because they can easily be electrically contacted. Here we demonstrate photon upconversion with a large energy shift in highly n-doped InP nanowires. Crucially, the mechanism responsible for the upconversion in our system does not rely on multi-photon absorption via intermediate states, thus eliminating the need for high photon fluxes to achieve upconversion. The demonstrated upconversion paves the way for utilizing nanowires--with their inherent flexibility such as electrical contactability and the ability to position individual nanowires--for photon upconversion devices also at low photon fluxes, possibly down to the single photon level in optimised structures.

关键词： nanowires photon upconversion photoluminescence indium phosphide

Valence Band Splitting in Wurtzite InP Nanowires Observed by Photoluminescence and Photoluminescence Excitation Spectroscopy

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Nano Research 2011年第2期4卷 159-163页

作者： Gerben L. Tuin magnus T. borgstrom Johanna Tragardh Martin Ek L. Reine Wallenberg Lars Samuelson Mats-Erik Pistol Solid State Physics/Nanometer Structure Consortium Box 118 Lund University S-221 00 Lund Sweden Polymer ＆ Materials Chemistry/nCHREM Lund University S-22100 Lurid Sweden

我们用光致发光，光致发光刺激光谱学和传播电子显微镜学调查了 wurtzite InP 的单个像体积的电线。用二个不同方法，我们发现原子价乐队的顶被切开，理论上期望。这切开原子价乐队对 wurtzite InP 古怪并且不发生在锌闪锌矿 InP。我们... 详细信息

我们用光致发光，光致发光刺激光谱学和传播电子显微镜学调查了 wurtzite InP 的单个像体积的电线。用二个不同方法，我们发现原子价乐队的顶被切开，理论上期望。这切开原子价乐队对 wurtzite InP 古怪并且不发生在锌闪锌矿 InP。我们发现二个乐队之间的精力差别是 40 兆电子伏。

关键词：光致发光激发光谱纤锌矿结构 InP 分裂价带纳米线透射电子显微镜闪锌矿

High resolution strain mapping of a single axially heterostructured nanowire using scanning X-ray diffraction

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Nano Research 2020年第9期13卷 2460-2468页

作者： Susanna Hammarberg Vilgaile Dagyte Lert Chayanun Megan O.Hill Alexander Wyke Alexander Bjorling Ulf Johansson Sebastian Kalbfleisch magnus Heurlin Lincoln J.Lauhon magnus T.borgstrom Jesper Wallentin Synchrotron Radiation Research and NanoLund Lund UniversityBox 118Lund 22100Sweden Solid State Physics and NanoLund Lund UniversityBox 118Lund 22100Sweden Department of Materials Science and Engineering Northwestern UniversityEvanstonIllinois 60208USA MAX IV Laboratory Lund UniversityBox 118Lund 22100Sweden

Axially heterostructured nanowires are a promising platform for next generation electronic and optoelectronic *** based on theoretical modeling have predicted more complex strain distributions and increased critical layer thicknesses than in thin films,due to lateral strain relaxation at the surface,but the understanding of the growth and strain distributions in these complex structures is hampered by the lack of high-resolution characterization ***,we demonstrate strain mapping of an axially segmented GalnP-lnP 190 nm diameter nanowire heterostructure using scanning X-ray *** systematically investigate the strain distribution and lattice tilt in three different segment lengths from 45 to 170 nm,obtaining strain maps with about 10^-4 relative strain *** experiments were performed using the 90 nm diameter nanofocus at the NanoMAX beamline,taking advantage of the high coherent flux from the first diffraction limited storage ring MAX *** experimental results are in good agreement with a full simulation of the experiment based on a three-dimensional(3D)finite element *** largest segments show a complex profile,where the lateral strain relaxation at the surface leads to a dome-shaped strain distribution from the mismatched interfaces,and a change from tensile to compressive strain within a single *** lattice tilt maps show a cross-shaped profile with excellent qualitative and quantitative agreement with the *** contrast,the shortest measured InP segment is almost fully adapted to the surrounding GalnP segments.

关键词： strain mapping nanowire heterostructure X-ray diffraction(XRD) MAX IV finite element modeling

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

Time trends and outcomes of gastrostomy placement in a Swedish national cohort over two decades

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World Journal of Gastroenterology 2024年第10期30卷 1358-1367页

作者： Martin Löfling Skogar magnus Sundbom Department of Surgical Sciences Uppsala UniversityUppsala 75185Sweden

BACKGROUND Percutaneous endoscopic gastrostomy(PEG)and laparoscopically inserted gastrostomy have become the gold standard for adult patients and children,respectively,requiring long-term enteral nutrition ***-related mortality is a rare event,often reported to be zero in smaller *** data on 30-d mortality and long-term survival rates after gastrostomy placement are scarce in the *** To study the use of gastrostomies in Sweden from 1998-2019 and to analyze procedure-related mortality and short-term(<30 d)and long-term *** In this retrospective,population-based cohort study,individuals that had received a gastrostomy between 1998-2019 in Sweden were *** were identified in the Swedish National Patient Register,and survival analysis was possible by cross-referencing the Swedish Death *** cohort was divided into three age groups:Children(0-18 years);adults(19-64 years);and elderly(≥65 years).Kaplan-Meier with log-rank test and Cox regression were used for survival *** In total 48682 individuals(52%males,average age 60.9±25.3 years)were *** cohort consisted of 12.0%children,29.5%adults,and 58.5%*** increased use of gastrostomies was observed during the study period,from 13.7/100000 to 22.3/100000 individuals(P<0.001).The use of PEG more than doubled(about 800 to 1800/year),with a corresponding decrease in open gastrostomy(about 700 to 340/year).Laparoscopic gastrostomy increased more than ten-fold(about 20 to 240/year).Overall,PEG,open gastrostomy,and laparoscopic gastrostomy constituted 70.0%(n=34060),23.3%(n=11336),and 4.9%(n=2404),***-related mortality was 0.1%(n=44)overall(PEG:0.05%,open:0.24%,laparoscopic:0.04%).The overall 30-d mortality rate was 10.0%(PEG:9.8%,open:12.4%,laparoscopic:1.7%)and decreased from 11.6%in 1998-2009 vs 8.5%in 2010-2019(P<0.001).One-year and ten-year survival rates for children,adults,and elderly were 93.7%,67.5%,a

关键词： Gastrostomy Percutaneous endoscopic gastrostomy Dysphagia Enteral nutrition Long-term Survival Complication

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基于拍卖理论的动态多代理同类机调度算法

Engineering 2024年第4期35卷 32-45页

作者： Yaqiong Liu Shudong Sun Gaopan Shen Xi Vincent Wang magnus Wiktorsson Lihui Wang Department of Industrial Engineering Northwestern Polytechnical UniversityXi’an 710072China Key Laboratory of Industrial Engineering and Intelligent Manufacturing Ministry of Industry and Information TechnologyXi’an 710072China Department of Production Engineering KTH Royal Institute of TechnologyStockholm 10044Sweden

This paper addresses a multi-agent scheduling problem with uniform parallel machines owned by a resource agent and competing jobs with dynamic arrival times that belong to different consumer *** agents are self-interested and rational with the aim of maximizing their own objectives,resulting in intense resource competition among consumer agents and strategic behaviors of unwillingness to disclose private *** the context,a centralized scheduling approach is unfeasible,and a decentralized approach is considered to deal with the targeted *** study aims to generate a stable and collaborative solution with high social welfare while simultaneously accommodating consumer agents’preferences under incomplete *** this purpose,a dynamic iterative auction-based approach based on a decentralized decision-making procedure is *** the proposed approach,a dynamic auction procedure is established for dynamic jobs participating in a realtime auction,and a straightforward and easy-to-implement bidding strategy without price is presented to reduce the complexity of bid *** addition,an adaptive Hungarian algorithm is applied to solve the winner determination problem efficiently.A theoretical analysis is conducted to prove that the proposed approach is individually rational and that the myopic bidding strategy is a weakly dominant strategy for consumer agents submitting *** computational experiments demonstrate that the developed approach achieves high-quality solutions and exhibits considerable stability on largescale problems with numerous consumer agents and jobs.A further multi-agent scheduling problem considering multiple resource agents will be studied in future work.

关键词： Multi-agent scheduling Decentralized scheduling Auction Dynamic jobs Private information