1
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Masteghin MG, Murdin BN, Duffy DA, Clowes SK, Cox DC, Sweeney SJ, Webb RP. Advancements and challenges in strained group-IV-based optoelectronic materials stressed by ion beam treatment. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:431501. [PMID: 39058285 DOI: 10.1088/1361-648x/ad649f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 07/17/2024] [Indexed: 07/28/2024]
Abstract
In this perspective article, we discuss the application of ion implantation to manipulate strain (by either neutralizing or inducing compressive or tensile states) in suspended thin films. Emphasizing the pressing need for a high-mobility silicon-compatible transistor or a direct bandgap group-IV semiconductor that is compatible with complementary metal-oxide-semiconductor technology, we underscore the distinctive features of different methods of ion beam-induced alteration of material morphology. The article examines the precautions needed during experimental procedures and data analysis and explores routes for potential scalable adoption by the semiconductor industry. Finally, we briefly discuss how this highly controllable strain-inducing technique can facilitate enhanced manipulation of impurity-based spin quantum bits (qubits).
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Affiliation(s)
- Mateus G Masteghin
- Advanced Technology Institute, University of Surrey, Guildford GU2 7XH, United Kingdom
| | - Benedict N Murdin
- Advanced Technology Institute, University of Surrey, Guildford GU2 7XH, United Kingdom
| | - Dominic A Duffy
- Advanced Technology Institute, University of Surrey, Guildford GU2 7XH, United Kingdom
- James Watt School of Engineering, University of Glasgow, Glasgow G12 8LT, United Kingdom
- ZiNIR Ltd, Eastbourne, United Kingdom
| | - Steven K Clowes
- Advanced Technology Institute, University of Surrey, Guildford GU2 7XH, United Kingdom
| | - David C Cox
- Advanced Technology Institute, University of Surrey, Guildford GU2 7XH, United Kingdom
| | - Stephen J Sweeney
- Advanced Technology Institute, University of Surrey, Guildford GU2 7XH, United Kingdom
- James Watt School of Engineering, University of Glasgow, Glasgow G12 8LT, United Kingdom
- ZiNIR Ltd, Eastbourne, United Kingdom
| | - Roger P Webb
- Ion Beam Centre, University of Surrey, Guildford GU2 7XH, United Kingdom
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2
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Krotkus A, Nevinskas I, Norkus R. Semiconductor Characterization by Terahertz Excitation Spectroscopy. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2859. [PMID: 37049153 PMCID: PMC10096385 DOI: 10.3390/ma16072859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/15/2023] [Accepted: 03/27/2023] [Indexed: 06/19/2023]
Abstract
Surfaces of semiconducting materials excited by femtosecond laser pulses emit electromagnetic waves in the terahertz (THz) frequency range, which by definition is the 0.1-10 THz region. The nature of terahertz radiation pulses is, in the majority of cases, explained by the appearance of ultrafast photocurrents. THz pulse duration is comparable with the photocarrier momentum relaxation time, thus such hot-carrier effects as the velocity overshoot, ballistic carrier motion, and optical carrier alignment must be taken into consideration when explaining experimental observations of terahertz emission. Novel commercially available tools such as optical parametric amplifiers that are capable of generating femtosecond optical pulses within a wide spectral range allow performing new unique experiments. By exciting semiconductor surfaces with various photon energies, it is possible to look into the ultrafast processes taking place at different electron energy levels of the investigated materials. The experimental technique known as the THz excitation spectroscopy (TES) can be used as a contactless method to study the band structure and investigate the ultrafast processes of various technologically important materials. A recent decade of investigations with the THz excitation spectroscopy method is reviewed in this article. TES experiments performed on the common bulk A3B5 compounds such as the wide-gap GaAs, and narrow-gap InAs and InSb, as well as Ge, Te, GaSe and other bulk semiconductors are reviewed. Finally, the results obtained by this non-contact technique on low-dimensional materials such as ultrathin mono-elemental Bi films, InAs, InGaAs, and GaAs nanowires are also presented.
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3
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Jacob B, Camarneiro F, Borme J, Bondarchuk O, Nieder JB, Romeira B. Surface Passivation of III-V GaAs Nanopillars by Low-Frequency Plasma Deposition of Silicon Nitride for Active Nanophotonic Devices. ACS APPLIED ELECTRONIC MATERIALS 2022; 4:3399-3410. [PMID: 36570334 PMCID: PMC9778088 DOI: 10.1021/acsaelm.2c00195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Numerous efforts have been devoted to improve the electronic and optical properties of III-V compound materials via reduction of their nonradiative states, aiming at highly efficient III-V sub-micrometer active devices and circuits. Despite many advances, the poor reproducibility and short-term passivation effect of chemical treatments, such as sulfidation and nitridation, requires the use of protective encapsulation methods, not only to protect the surface, but also to provide electrical isolation for device manufacturing. There is still a controversial debate on which combination of chemical treatment and capping dielectric layer can best reproducibly protect the crystal surface of III-V materials while being compatible with readily available semiconductor-foundry plasma deposition methods. This work reports on a systematic experimental study on the role of sulfide ammonium chemical treatment followed by dielectric coating (either silicon oxide or nitride) in the passivation effect of GaAs/AlGaAs nanopillars. Our results conclusively show that, under ambient conditions, the best surface passivation is achieved using ammonium sulfide followed by encapsulation with a thin layer of silicon nitride by low-frequency plasma-enhanced chemical deposition. Here, the sulfurized GaAs surfaces, high level of hydrogen ions, and low-frequency (380 kHz) excitation plasma that enable intense bombardment of hydrogen, all seem to provide a combined active role in the passivation mechanism of the pillars by reducing the surface states. As a result, we observe up to a 29-fold increase of the photoluminescence (PL) integrated intensity for the best samples as compared to untreated nanopillars. X-ray photoelectron spectroscopy analysis confirms the best treatments show remarkable removal of gallium and arsenic native oxides. Time-resolved micro-PL measurements display nanosecond lifetimes resulting in a record-low surface recombination velocity of ∼1.1 × 104 cm s-1 for dry-etched GaAs nanopillars. We achieve robust, stable, and long-term passivated nanopillar surfaces, which creates expectations for remarkable high internal quantum efficiency (IQE > 0.5) in nanoscale light-emitting diodes. The enhanced performance paves the way to many other nanostructures and devices such as miniature resonators, lasers, photodetectors, and solar cells, opening remarkable prospects for GaAs active nanophotonic devices.
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Affiliation(s)
- Bejoys Jacob
- INL
− International Iberian Nanotechnology Laboratory, Ultrafast
Bio- and Nanophotonics group, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal
| | - Filipe Camarneiro
- INL
− International Iberian Nanotechnology Laboratory, Ultrafast
Bio- and Nanophotonics group, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal
| | - Jérôme Borme
- INL
− International Iberian Nanotechnology Laboratory, 2D Materials
and Devices group, Av.
Mestre José Veiga s/n, 4715-330 Braga, Portugal
| | - Oleksandr Bondarchuk
- INL
− International Iberian Nanotechnology Laboratory, Advanced
Electron Microscopy, Imaging and Spectroscopy Facility, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal
| | - Jana B. Nieder
- INL
− International Iberian Nanotechnology Laboratory, Ultrafast
Bio- and Nanophotonics group, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal
| | - Bruno Romeira
- INL
− International Iberian Nanotechnology Laboratory, Ultrafast
Bio- and Nanophotonics group, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal
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4
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Chen L, Adeyemo SO, Fonseka HA, Liu H, Kar S, Yang H, Velichko A, Mowbray DJ, Cheng Z, Sanchez AM, Joyce HJ, Zhang Y. Long-Term Stability and Optoelectronic Performance Enhancement of InAsP Nanowires with an Ultrathin InP Passivation Layer. NANO LETTERS 2022; 22:3433-3439. [PMID: 35420433 PMCID: PMC9097579 DOI: 10.1021/acs.nanolett.2c00805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/25/2022] [Indexed: 06/14/2023]
Abstract
The influence of nanowire (NW) surface states increases rapidly with the reduction of diameter and hence severely degrades the optoelectronic performance of narrow-diameter NWs. Surface passivation is therefore critical, but it is challenging to achieve long-term effective passivation without significantly affecting other qualities. Here, we demonstrate that an ultrathin InP passivation layer of 2-3 nm can effectively solve these challenges. For InAsP nanowires with small diameters of 30-40 nm, the ultrathin passivation layer reduces the surface recombination velocity by at least 70% and increases the charge carrier lifetime by a factor of 3. These improvements are maintained even after storing the samples in ambient atmosphere for over 3 years. This passivation also greatly improves the performance thermal tolerance of these thin NWs and extends their operating temperature from <150 K to room temperature. This study provides a new route toward high-performance room-temperature narrow-diameter NW devices with long-term stability.
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Affiliation(s)
- LuLu Chen
- School
of Micro-Nano Electronics, Zhejiang University, Hangzhou, Zhejiang 311200, China
| | - Stephanie O. Adeyemo
- Electrical
Engineering Division, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - H. Aruni Fonseka
- Department
of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Huiyun Liu
- Department
of Electronic and Electrical Engineering, University College London, London WC1E 7JE, United Kingdom
| | - Srabani Kar
- Electrical
Engineering Division, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Hui Yang
- Institute
for Materials Discovery, University College
London, Roberts Building, Malet Place, London, WC1E 7JE, United Kingdom
| | - Anton Velichko
- Department
of Physics and Astronomy and the Photon Science Institute, University of Sheffield, Sheffield S3 7RH, United Kingdom
| | - David J. Mowbray
- Department
of Physics and Astronomy and the Photon Science Institute, University of Sheffield, Sheffield S3 7RH, United Kingdom
| | - Zhiyuan Cheng
- School
of Micro-Nano Electronics, Zhejiang University, Hangzhou, Zhejiang 311200, China
| | - Ana M. Sanchez
- Department
of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Hannah J Joyce
- Electrical
Engineering Division, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Yunyan Zhang
- School
of Micro-Nano Electronics, Zhejiang University, Hangzhou, Zhejiang 311200, China
- Department
of Electronic and Electrical Engineering, University College London, London WC1E 7JE, United Kingdom
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5
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Abstract
Transistor concepts based on semiconductor nanowires promise high performance, lower energy consumption and better integrability in various platforms in nanoscale dimensions. Concerning the intrinsic transport properties of electrons in nanowires, relatively high mobility values that approach those in bulk crystals have been obtained only in core/shell heterostructures, where electrons are spatially confined inside the core. Here, it is demonstrated that the strain in lattice-mismatched core/shell nanowires can affect the effective mass of electrons in a way that boosts their mobility to distinct levels. Specifically, electrons inside the hydrostatically tensile-strained gallium arsenide core of nanowires with a thick indium aluminium arsenide shell exhibit mobility values 30–50 % higher than in equivalent unstrained nanowires or bulk crystals, as measured at room temperature. With such an enhancement of electron mobility, strained gallium arsenide nanowires emerge as a unique means for the advancement of transistor technology. Semiconductor nanowires are promising candidates for the realization of novel transistor concepts. Here, the authors demonstrate that electron mobility in strained coaxial nanowire heterostructures can be higher than in the corresponding bulk crystals.
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6
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Azimi Z, Gagrani N, Qu J, Lem OLC, Mokkapati S, Cairney JM, Zheng R, Tan HH, Jagadish C, Wong-Leung J. Understanding the role of facets and twin defects in the optical performance of GaAs nanowires for laser applications. NANOSCALE HORIZONS 2021; 6:559-567. [PMID: 33999985 DOI: 10.1039/d1nh00079a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
GaAs nanowires are regarded as promising building blocks of future optoelectronic devices. Despite progress, the growth of high optical quality GaAs nanowires is a standing challenge. Understanding the role of twin defects and nanowire facets on the optical emission and minority carrier lifetime of GaAs nanowires is key for the engineering of their optoelectronic properties. Here, we present new insights into the microstructural parameters controlling the optical properties of GaAs nanowires, grown via selective-area metal-organic vapor-phase epitaxy. We observe that these GaAs nanowires have a twinned zinc blende crystal structure with taper-free {110} side facets that result in an ultra-low surface recombination velocity of 3.5 × 104 cm s-1. This is an order of magnitude lower than that reported for defect-free GaAs nanowires grown by the vapor-liquid-solid technique. Using time-resolved photoluminescence and cathodoluminescence measurements, we untangle the local correlation between structural and optical properties demonstrating the superior role of the side facets in determining recombination rates over that played by twin defects. The low surface recombination velocity of these taper-free {110} side facets enable us to demonstrate, for the first time, low-temperature lasing from bare (unpassivated) GaAs nanowires, and also efficient room-temperature lasing after passivation with an AlGaAs shell.
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Affiliation(s)
- Zahra Azimi
- Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, Australia.
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7
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Al-Abri R, Choi H, Parkinson P. Measuring, controlling and exploiting heterogeneity in optoelectronic nanowires. JPHYS PHOTONICS 2021. [DOI: 10.1088/2515-7647/abe282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Abstract
Fabricated from ZnO, III-N, chalcogenide-based, III-V, hybrid perovskite or other materials, semiconductor nanowires offer single-element and array functionality as photovoltaic, non-linear, electroluminescent and lasing components. In many applications their advantageous properties emerge from their geometry; a high surface-to-volume ratio for facile access to carriers, wavelength-scale dimensions for waveguiding or a small nanowire-substrate footprint enabling heterogeneous growth. However, inhomogeneity during bottom-up growth is ubiquitous and can impact morphology, geometry, crystal structure, defect density, heterostructure dimensions and ultimately functional performance. In this topical review, we discuss the origin and impact of heterogeneity within and between optoelectronic nanowires, and introduce methods to assess, optimise and ultimately exploit wire-to-wire disorder.
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8
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Jiang N, Joyce HJ, Parkinson P, Wong-Leung J, Tan HH, Jagadish C. Facet-Related Non-uniform Photoluminescence in Passivated GaAs Nanowires. Front Chem 2020; 8:607481. [PMID: 33365302 PMCID: PMC7750184 DOI: 10.3389/fchem.2020.607481] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 11/05/2020] [Indexed: 11/13/2022] Open
Abstract
The semiconductor nanowire architecture provides opportunities for non-planar electronics and optoelectronics arising from its unique geometry. This structure gives rise to a large surface area-to-volume ratio and therefore understanding the effect of nanowire surfaces on nanowire optoelectronic properties is necessary for engineering related devices. We present a systematic study of the non-uniform optical properties of Au-catalyzed GaAs/AlGaAs core–shell nanowires introduced by changes in the sidewall faceting. Significant variation in intra-wire photoluminescence (PL) intensity and PL lifetime (τPL) was observed along the nanowire axis, which was strongly correlated with the variation of sidewall facets from {112} to {110} from base to tip. Faster recombination occurred in the vicinity of {112}-oriented GaAs/AlGaAs interfaces. An alternative nanowire heterostructure, the radial quantum well tube consisting of a GaAs layer sandwiched between two AlGaAs barrier layers, is proposed and demonstrates superior uniformity of PL emission along the entire length of nanowires. The results emphasize the significance of nanowire facets and provide important insights for nanowire device design.
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Affiliation(s)
- Nian Jiang
- Electrical Engineering Division, Engineering Department, University of Cambridge, Cambridge, United Kingdom
| | - Hannah J Joyce
- Electrical Engineering Division, Engineering Department, University of Cambridge, Cambridge, United Kingdom
| | - Patrick Parkinson
- Department of Physics and Astronomy, The Photon Science Institute, University of Manchester, Manchester, United Kingdom
| | - Jennifer Wong-Leung
- Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, ACT, Australia
| | - Hark Hoe Tan
- Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, ACT, Australia.,Australian Research Council (ARC) Centre of Excellence for Transformative Meta-Optical Systems, Research School of Physics, The Australian National University, Canberra, ACT, Australia
| | - Chennupati Jagadish
- Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, ACT, Australia.,Australian Research Council (ARC) Centre of Excellence for Transformative Meta-Optical Systems, Research School of Physics, The Australian National University, Canberra, ACT, Australia
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9
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Garming MWH, Bolhuis M, Conesa-Boj S, Kruit P, Hoogenboom JP. Lock-in Ultrafast Electron Microscopy Simultaneously Visualizes Carrier Recombination and Interface-Mediated Trapping. J Phys Chem Lett 2020; 11:8880-8886. [PMID: 32909435 PMCID: PMC7569669 DOI: 10.1021/acs.jpclett.0c02345] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/10/2020] [Indexed: 06/11/2023]
Abstract
Visualizing charge carrier flow over interfaces or near surfaces meets great challenges concerning resolution and vastly different time scales of bulk and surface dynamics. Ultrafast or four-dimensional scanning electron microscopy (USEM) using a laser pump electron probe scheme circumvents the optical diffraction limit, but disentangling surface-mediated trapping and ultrafast carrier dynamics in a single measurement scheme has not yet been demonstrated. Here, we present lock-in USEM, which simultaneously visualizes fast bulk recombination and slow trapping. As a proof of concept, we show that the surface termination on GaAs, i.e., Ga or As, profoundly influences ultrafast movies. We demonstrate the differences can be attributed to trapping-induced surface voltages of approximately 100-200 mV, which is further supported by secondary electron particle tracing calculations. The simultaneous visualization of both competing processes opens new perspectives for studying carrier transport in layered, nanostructured, and two-dimensional semiconductors, where carrier trapping constitutes a major bottleneck for device efficiency.
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Affiliation(s)
- Mathijs W. H. Garming
- Department
of Imaging Physics, Delft University of
Technology, 2628 CN Delft, The Netherlands
| | - Maarten Bolhuis
- Kavli
Institute of Nanoscience, Delft University
of Technology, 2628 CJ Delft, The Netherlands
| | - Sonia Conesa-Boj
- Kavli
Institute of Nanoscience, Delft University
of Technology, 2628 CJ Delft, The Netherlands
| | - Pieter Kruit
- Department
of Imaging Physics, Delft University of
Technology, 2628 CN Delft, The Netherlands
| | - Jacob P. Hoogenboom
- Department
of Imaging Physics, Delft University of
Technology, 2628 CN Delft, The Netherlands
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10
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Yu P, Li Z, Wu T, Wang YT, Tong X, Li CF, Wang Z, Wei SH, Zhang Y, Liu H, Fu L, Zhang Y, Wu J, Tan HH, Jagadish C, Wang ZM. Nanowire Quantum Dot Surface Engineering for High Temperature Single Photon Emission. ACS NANO 2019; 13:13492-13500. [PMID: 31689076 DOI: 10.1021/acsnano.9b07204] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Generating single photons at high temperature remains a major challenge, particularly for group III-As and III-P materials widely used in optical communication. Here, we report a high temperature single photon emitter based on a "surface-free" GaAs quantum dot (QD) in a GaAsP nanowire. By using self-catalyzed vapor-liquid-solid growth and simple surface engineering, we can significantly enhance the optical signal from the QDs with a highly polarized photoluminescence at 750 nm. The "surface-free" nanowire quantum dots show photon antibunching up to 160 K and well resolved exciton lines as high as 220 K.
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Affiliation(s)
- Peng Yu
- Institute of Fundamental and Frontier Sciences , University of Electronic Science and Technology of China , Chengdu 610054 , P. R. China
- Department of Electronic Materials Engineering, Research School of Physics and Engineering , The Australian National University , Canberra , ACT 2601 , Australia
| | - Ziyuan Li
- Department of Electronic Materials Engineering, Research School of Physics and Engineering , The Australian National University , Canberra , ACT 2601 , Australia
| | - Tongwei Wu
- Institute of Fundamental and Frontier Sciences , University of Electronic Science and Technology of China , Chengdu 610054 , P. R. China
| | - Yi-Tao Wang
- Key Laboratory of Quantum Information , University of Science and Technology of China, CAS , Hefei 230026 , China
| | - Xin Tong
- Institute of Fundamental and Frontier Sciences , University of Electronic Science and Technology of China , Chengdu 610054 , P. R. China
| | - Chuan-Feng Li
- Key Laboratory of Quantum Information , University of Science and Technology of China, CAS , Hefei 230026 , China
| | - Zhongchang Wang
- Department of Quantum and Energy Materials , International Iberian Nanotechnology Laboratory (INL) , Braga 4715-330 , Portugal
| | - Su-Huai Wei
- Beijing Computational Science Research Center , Beijing 100094 , China
| | - Yunyan Zhang
- Department of Electronic and Electrical Engineering , University College London , London WC1E 7JE , United Kingdom
| | - Huiyun Liu
- Department of Electronic and Electrical Engineering , University College London , London WC1E 7JE , United Kingdom
| | - Lan Fu
- Department of Electronic Materials Engineering, Research School of Physics and Engineering , The Australian National University , Canberra , ACT 2601 , Australia
| | - Yanning Zhang
- Institute of Fundamental and Frontier Sciences , University of Electronic Science and Technology of China , Chengdu 610054 , P. R. China
| | - Jiang Wu
- Institute of Fundamental and Frontier Sciences , University of Electronic Science and Technology of China , Chengdu 610054 , P. R. China
| | - Hark Hoe Tan
- Department of Electronic Materials Engineering, Research School of Physics and Engineering , The Australian National University , Canberra , ACT 2601 , Australia
| | - Chennupati Jagadish
- Institute of Fundamental and Frontier Sciences , University of Electronic Science and Technology of China , Chengdu 610054 , P. R. China
- Department of Electronic Materials Engineering, Research School of Physics and Engineering , The Australian National University , Canberra , ACT 2601 , Australia
| | - Zhiming M Wang
- Institute of Fundamental and Frontier Sciences , University of Electronic Science and Technology of China , Chengdu 610054 , P. R. China
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11
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Zhang K, Li X, Dai W, Toor F, Prineas JP. Carrier Recombination in the Base, Interior, and Surface of InAs/InAlAs Core-Shell Nanowires Grown on Silicon. NANO LETTERS 2019; 19:4272-4278. [PMID: 31244233 DOI: 10.1021/acs.nanolett.9b00517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We report on carrier recombination within self-catalyzed InAs/InAlAs core-shell nanowires (NWs), disentangling recombination rates at the ends, sidewalls, and interior of the NWs. Ultrafast optical pump-probe spectroscopy measurements were performed from 77-293 K on the free-standing, variable-sized NWs grown on lattice-mismatched Si(111) substrates, independently varying NW length and diameter. We found NW carrier recombination in the interior is nontrivial compared to the surface recombination, especially at 293 K. Surface recombination is dominated by carrier recombination at the NW sidewall, while contributions from the highly strained, impure NW base are negligible.
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12
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Fan P, Liu H, Zhuang X, Zheng W, Ge C, Huang W, Yang X, Liu Y, Jiang Y, Zhu X, Pan A. Ultra-long distance carrier transportation in bandgap-graded CdS xSe 1-x nanowire waveguides. NANOSCALE 2019; 11:8494-8501. [PMID: 30990510 DOI: 10.1039/c9nr01800j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Carrier transportation in semiconductor nanowires is essential for their application in integrated opto-electronic devices. Therefore, it is of importance to manipulate and enhance the transportation performance of nanowires through micro-nano scale engineering. In this work, the carrier dynamics of the waveguides in the bandgap-graded CdSxSe1-x nanowires is systematically investigated. By developing a spatially separated time-resolved photoluminescence spectroscopy system, the dependence between the propagation distance/direction and the dynamics of the bandgap gradient driven long-range carrier transportation of the nanowires is characterized. In the meantime, the dynamics of carrier concentration driven spontaneous diffusion is also characterized to be compared to. It is found that the continuous carrier transportation which is driven by the bandgap gradient is the dominant process in the active waveguide, where the maximum transportation distance of 100 μm is detected. Such a transportation distance is up to ∼8-fold larger than the spontaneous carrier diffusion distance in the bandgap-graded CdSxSe1-x nanowires. The ultra-long carrier transportation capability in the bandgap gradient nanowires makes them ideal structures for applications in long-distance photo-energy delivery and micro-nanoscale opto-electronics.
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Affiliation(s)
- Peng Fan
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China.
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13
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Alanis JA, Lysevych M, Burgess T, Saxena D, Mokkapati S, Skalsky S, Tang X, Mitchell P, Walton AS, Tan HH, Jagadish C, Parkinson P. Optical Study of p-Doping in GaAs Nanowires for Low-Threshold and High-Yield Lasing. NANO LETTERS 2019; 19:362-368. [PMID: 30525674 DOI: 10.1021/acs.nanolett.8b04048] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Semiconductor nanowires suffer from significant non-radiative surface recombination; however, heavy p-type doping has proven to be a viable option to increase the radiative recombination rate and, hence, quantum efficiency of emission, allowing the demonstration of room-temperature lasing. Using a large-scale optical technique, we have studied Zn-doped GaAs nanowires to understand and quantify the effect of doping on growth and lasing properties. We measure the non-radiative recombination rate ( knr) to be (0.14 ± 0.04) ps-1 by modeling the internal quantum efficiency (IQE) as a function of doping level. By applying a correlative method, we identify doping and nanowire length as key controllable parameters determining lasing behavior, with reliable room-temperature lasing occurring for p ≳ 3 × 1018 cm-3 and lengths of ≳4 μm. We report a best-in-class core-only near-infrared nanowire lasing threshold of ∼10 μJ cm-2, and using a data-led filtering step, we present a method to simply identify subsets of nanowires with over 90% lasing yield.
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Affiliation(s)
| | | | | | - Dhruv Saxena
- The Blackett Laboratory, Department of Physics , Imperial College London , London SW7 2AZ , United Kingdom
| | - Sudha Mokkapati
- School of Physics and Astronomy and the Institute for Compound Semiconductors , Cardiff University , Cardiff , CF10 3AT , United Kingdom
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14
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Ren D, Rong Z, Somasundaram S, Azizur-Rahman KM, Liang B, Huffaker DL. A three-dimensional insight into correlation between carrier lifetime and surface recombination velocity for nanowires. NANOTECHNOLOGY 2018; 29:504003. [PMID: 30240365 DOI: 10.1088/1361-6528/aae365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The performance of nanowire-based devices is predominantly affected by nonradiative recombination on their surfaces, or sidewalls, due to large surface-to-volume ratios. A common approach to quantitatively characterize surface recombination is to implement time-resolved photoluminescence to correlate surface recombination velocity with measured minority carrier lifetime by a conventional analytical equation. However, after using numerical simulations based on a three-dimensional (3D) transient model, we assert that the correlation between minority carrier lifetime and surface recombination velocity is dependent on a more complex combination of factors, including nanowire geometry, energy-band alignment, and spatial carrier diffusion in 3D. To demonstrate this assertion, we use three cases-GaAs nanowires, InGaAs nanowires, and InGaAs inserts embedded in GaAs nanowires-and numerically calculate the carrier lifetimes by varying the surface recombination velocities. Using this information, we then investigate the intrinsic carrier dynamics within those 3D structures. We argue that the conventional analytical approach to determining surface recombination in nanowires is of limited applicability, and that a comprehensive computation in 3D can provide more accurate analysis. Our study provides a solid theoretical foundation to further understand surface characteristics and carrier dynamics for 3D nanostructured materials.
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Affiliation(s)
- Dingkun Ren
- Department of Electrical and Computer Engineering, University of California, Los Angeles, Los Angeles, CA 90095, United States of America
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15
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Yang W, Pan D, Shen R, Wang X, Zhao J, Chen Q. Suppressing the excess OFF-state current of short-channel InAs nanowire field-effect transistors by nanoscale partial-gate. NANOTECHNOLOGY 2018; 29:415203. [PMID: 30052527 DOI: 10.1088/1361-6528/aad67c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The excess OFF-state current caused by band to band tunneling (BTBT) is a serious issue particularly in short-channel nanowire (NW) field-effect transistors (FETs), especially for narrow bandgap semiconductors such as InAs. Here, to clarify the components of the OFF-current and suppress the OFF-current, we for the first time fabricate and study InAs NW FETs with nanoscale partial-gate (PG). We fabricate a series of PGFETs and a normal full-gate (FG) FET on the same NW. Based on our results, the BTBT current component can reach tens of nanoamps in a typical 250 nm-channel InAs NW FGFET, and dominate the OFF-current. In contrast, there is almost no BTBT component in the PGFET, which provides a reference for other short-channel InAs NW FETs. Furthermore, the physical mechanism of the OFF-state carrier transport is discussed, and both electrons and holes currents are proven to be very important, based on our experimental results. Also, through statistic study, we find the BTBT effect can be more serious in the devices with better gate-control. Therefore, suppressing the BTBT effect is important to the future scaling-down.
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Affiliation(s)
- Wenyuan Yang
- Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University, Beijing 100871, People's Republic of China
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16
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Zeng L, Gammer C, Ozdol B, Nordqvist T, Nygård J, Krogstrup P, Minor AM, Jäger W, Olsson E. Correlation between Electrical Transport and Nanoscale Strain in InAs/In 0.6Ga 0.4As Core-Shell Nanowires. NANO LETTERS 2018; 18:4949-4956. [PMID: 30044917 PMCID: PMC6166997 DOI: 10.1021/acs.nanolett.8b01782] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 07/15/2018] [Indexed: 05/25/2023]
Abstract
Free-standing semiconductor nanowires constitute an ideal material system for the direct manipulation of electrical and optical properties by strain engineering. In this study, we present a direct quantitative correlation between electrical conductivity and nanoscale lattice strain of individual InAs nanowires passivated with a thin epitaxial In0.6Ga0.4As shell. With an in situ electron microscopy electromechanical testing technique, we show that the piezoresistive response of the nanowires is greatly enhanced compared to bulk InAs, and that uniaxial elastic strain leads to increased conductivity, which can be explained by a strain-induced reduction in the band gap. In addition, we observe inhomogeneity in strain distribution, which could have a reverse effect on the conductivity by increasing the scattering of charge carriers. These results provide a direct correlation of nanoscale mechanical strain and electrical transport properties in free-standing nanostructures.
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Affiliation(s)
- Lunjie Zeng
- Department
of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden
| | - Christoph Gammer
- Erich
Schmid Institute of Materials Science, Austrian
Academy of Sciences, 8700 Leoben, Austria
| | - Burak Ozdol
- National
Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Thomas Nordqvist
- Niels
Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Jesper Nygård
- Niels
Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Peter Krogstrup
- Niels
Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Andrew M. Minor
- National
Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department
of Materials Science and Engineering, University
of California, Berkeley, California 94720, United States
| | - Wolfgang Jäger
- Department
of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden
- Institute
of Materials Science, Christian-Albrechts-University
Kiel, 24118 Kiel, Germany
| | - Eva Olsson
- Department
of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden
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17
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Yan JY. Excitonic terahertz photoconductivity in intrinsic semiconductor nanowires. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:235301. [PMID: 29697063 DOI: 10.1088/1361-648x/aac044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Excitonic terahertz photoconductivity in intrinsic semiconductor nanowires is studied. Based on the excitonic theory, the numerical method to calculate the photoconductivity spectrum in the nanowires is developed, which can simulate optical pump terahertz-probe spectroscopy measurements on real nanowires and thereby calculate the typical photoconductivity spectrum. With the help of the energetic structure deduced from the calculated linear absorption spectrum, the numerically observed shift of the resonant peak in the photoconductivity spectrum is found to result from the dominant exciton transition between excited or continuum states to the ground state, and the quantitative analysis is in good agreement with the quantum plasmon model. Besides, the dependence of the photoconductivity on the polarization of the terahertz field is also discussed. The numerical method and supporting theoretical analysis provide a new tool for experimentalists to understand the terahertz photoconductivity in intrinsic semiconductor nanowires at low temperatures or for nanowires subjected to below bandgap photoexcitation, where excitonic effects dominate.
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Affiliation(s)
- Jie-Yun Yan
- School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, People's Republic of China
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18
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Ren D, Scofield AC, Farrell AC, Rong Z, Haddad MA, Laghumavarapu RB, Liang B, Huffaker DL. Exploring time-resolved photoluminescence for nanowires using a three-dimensional computational transient model. NANOSCALE 2018; 10:7792-7802. [PMID: 29663009 DOI: 10.1039/c8nr01908h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Time-resolved photoluminescence (TRPL) has been implemented experimentally to measure the carrier lifetime of semiconductors for decades. For the characterization of nanowires, the rich information embedded in TRPL curves has not been fully interpreted and meaningfully mapped to the respective material properties. This is because their three-dimensional (3-D) geometries result in more complicated mechanisms of carrier recombination than those in thin films and analytical solutions cannot be found for those nanostructures. In this work, we extend the intrinsic power of TRPL by developing a full 3-D transient model, which accounts for different material properties and drift-diffusion, to simulate TRPL curves for nanowires. To show the capability of the model, we perform TRPL measurements on a set of GaAs nanowire arrays grown on silicon substrates and then fit the measured data by tuning various material properties, including carrier mobility, Shockley-Read-Hall recombination lifetime, and surface recombination velocity at the GaAs-Si heterointerface. From the resultant TRPL simulations, we numerically identify the lifetime characteristics of those material properties. In addition, we computationally map the spatial and temporal electron distributions in nanowire segments and reveal the underlying carrier dynamics. We believe this study provides a theoretical foundation for interpretation of TRPL measurements to unveil the complex carrier recombination mechanisms in 3-D nanostructured materials.
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Affiliation(s)
- Dingkun Ren
- Department of Electrical and Computer Engineering, University of California at Los Angeles, Los Angeles, California 90095, USA.
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19
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Alexander-Webber JA, Groschner CK, Sagade AA, Tainter G, Gonzalez-Zalba MF, Di Pietro R, Wong-Leung J, Tan HH, Jagadish C, Hofmann S, Joyce HJ. Engineering the Photoresponse of InAs Nanowires. ACS APPLIED MATERIALS & INTERFACES 2017; 9:43993-44000. [PMID: 29171260 DOI: 10.1021/acsami.7b14415] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We report on individual-InAs nanowire optoelectronic devices which can be tailored to exhibit either negative or positive photoconductivity (NPC or PPC). The NPC photoresponse time and magnitude is found to be highly tunable by varying the nanowire diameter under controlled growth conditions. Using hysteresis characterization, we decouple the observed photoexcitation-induced hot electron trapping from conventional electric field-induced trapping to gain a fundamental insight into the interface trap states responsible for NPC. Furthermore, we demonstrate surface passivation without chemical etching which both enhances the field-effect mobility of the nanowires by approximately an order of magnitude and effectively eliminates the hot carrier trapping found to be responsible for NPC, thus restoring an "intrinsic" positive photoresponse. This opens pathways toward engineering semiconductor nanowires for novel optical-memory and photodetector applications.
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Affiliation(s)
- Jack A Alexander-Webber
- Department of Engineering, University of Cambridge , 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Catherine K Groschner
- Department of Engineering, University of Cambridge , 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Abhay A Sagade
- Department of Engineering, University of Cambridge , 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
- SRM Research Institute, Department of Physics & Nanotechnology, SRM University , Kattankulathur 603 203, India
| | - Gregory Tainter
- Department of Engineering, University of Cambridge , 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | | | - Riccardo Di Pietro
- Hitachi Cambridge Laboratory , JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Jennifer Wong-Leung
- Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University , Canberra, ACT 2601, Australia
| | - H Hoe Tan
- Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University , Canberra, ACT 2601, Australia
| | - Chennupati Jagadish
- Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University , Canberra, ACT 2601, Australia
| | - Stephan Hofmann
- Department of Engineering, University of Cambridge , 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Hannah J Joyce
- Department of Engineering, University of Cambridge , 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
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20
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Yan JY. Quantum plasmon model for the terahertz photoconductivity in intrinsic semiconductor nanowires. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:415302. [PMID: 28869753 DOI: 10.1088/1361-648x/aa7fd2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A quantum plasmon model for the terahertz photoconductivity in intrinsic semiconductor nanowires is developed. The classical plasmon model assumes the excited electron in semiconductors feels a restoring force generated by a harmonic-oscillator potential. Although it is successfully applied to explain the terahertz photoconductivity in semiconductor nanowires, the classical treatment of the potential weakens accurate theoretical analysis. Here I treat the potential in a full quantum way and present an exact analytical formula for photoconductivity. The formula not only gives more reasonable photoconductivity, but also has the same conciseness when compared with that of the classical plasmon model. The validity of the quantum plasmon model is proved independently by numerical calculations in real space.
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Affiliation(s)
- Jie-Yun Yan
- School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, People's Republic of China. State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, People's Republic of China
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21
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Zhang W, Zeng X, Su X, Zou X, Mante PA, Borgström MT, Yartsev A. Carrier Recombination Processes in Gallium Indium Phosphide Nanowires. NANO LETTERS 2017; 17:4248-4254. [PMID: 28654299 DOI: 10.1021/acs.nanolett.7b01159] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Understanding of recombination and photoconductivity dynamics of photogenerated charge carriers in GaxIn1-xP NWs is essential for their optoelectronic applications. In this letter, we have studied a series of GaxIn1-xP NWs with varied Ga composition. Time-resolved photoinduced luminescence, femtosecond transient absorption, and time-resolved THz transmission measurements were performed to assess radiative and nonradiative recombination and photoconductivity dynamics of photogenerated charges in the NWs. We conclude that radiative recombination dynamics is limited by hole trapping, whereas electrons are highly mobile until they recombine nonradiatively. We also resolve gradual decrease of mobility of photogenerated electrons assigned to electron trapping and detrapping in a distribution of trap states. We identify that the nonradiative recombination of charges is much slower than the decay of the photoluminescence signal. Further, we conclude that trapping of both electrons and holes as well as nonradiative recombination become faster with increasing Ga composition in GaxIn1-xP NWs. We have estimated early time electron mobility in GaxIn1-xP NWs and found it to be strongly dependent on Ga composition due to the contribution of electrons in the X-valley.
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Affiliation(s)
- Wei Zhang
- NanoLund and Division of Chemical Physics, Lund University , Box 124, 221 00 Lund, Sweden
| | - Xulu Zeng
- NanoLund and Division of Solid State Physics, Lund University , Box 118, 221 00 Lund, Sweden
| | - Xiaojun Su
- NanoLund and Division of Chemical Physics, Lund University , Box 124, 221 00 Lund, Sweden
| | - Xianshao Zou
- NanoLund and Division of Chemical Physics, Lund University , Box 124, 221 00 Lund, Sweden
| | - Pierre-Adrien Mante
- NanoLund and Division of Chemical Physics, Lund University , Box 124, 221 00 Lund, Sweden
| | - Magnus T Borgström
- NanoLund and Division of Solid State Physics, Lund University , Box 118, 221 00 Lund, Sweden
| | - Arkady Yartsev
- NanoLund and Division of Chemical Physics, Lund University , Box 124, 221 00 Lund, Sweden
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22
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Higuera-Rodriguez A, Romeira B, Birindelli S, Black LE, Smalbrugge E, van Veldhoven PJ, Kessels WMM, Smit MK, Fiore A. Ultralow Surface Recombination Velocity in Passivated InGaAs/InP Nanopillars. NANO LETTERS 2017; 17:2627-2633. [PMID: 28340296 PMCID: PMC5391499 DOI: 10.1021/acs.nanolett.7b00430] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/22/2017] [Indexed: 05/26/2023]
Abstract
The III-V semiconductor InGaAs is a key material for photonics because it provides optical emission and absorption in the 1.55 μm telecommunication wavelength window. However, InGaAs suffers from pronounced nonradiative effects associated with its surface states, which affect the performance of nanophotonic devices for optical interconnects, namely nanolasers and nanodetectors. This work reports the strong suppression of surface recombination of undoped InGaAs/InP nanostructured semiconductor pillars using a combination of ammonium sulfide, (NH4)2S, chemical treatment and silicon oxide, SiOx, coating. An 80-fold enhancement in the photoluminescence (PL) intensity of submicrometer pillars at a wavelength of 1550 nm is observed as compared with the unpassivated nanopillars. The PL decay time of ∼0.3 μm wide square nanopillars is dramatically increased from ∼100 ps to ∼25 ns after sulfur treatment and SiOx coating. The extremely long lifetimes reported here, to our knowledge the highest reported to date for undoped InGaAs nanostructures, are associated with a record-low surface recombination velocity of ∼260 cm/s. We also conclusively show that the SiOx capping layer plays an active role in the passivation. These results are crucial for the future development of high-performance nanoscale optoelectronic devices for applications in energy-efficient data optical links, single-photon sensing, and photovoltaics.
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Affiliation(s)
- A. Higuera-Rodriguez
- Institute for Photonic Integration, Photonic Integration, Department
of Electrical Engineering, Photonics and Semiconductor Nanophysics, Department
of Applied Physics, Plasma and Materials Processing, Department of Applied Physics, and NanoLab@TU/eEindhoven University of Technology, Postbus 513, 5600
MB Eindhoven, The Netherlands
| | - B. Romeira
- Institute for Photonic Integration, Photonic Integration, Department
of Electrical Engineering, Photonics and Semiconductor Nanophysics, Department
of Applied Physics, Plasma and Materials Processing, Department of Applied Physics, and NanoLab@TU/eEindhoven University of Technology, Postbus 513, 5600
MB Eindhoven, The Netherlands
| | - S. Birindelli
- Institute for Photonic Integration, Photonic Integration, Department
of Electrical Engineering, Photonics and Semiconductor Nanophysics, Department
of Applied Physics, Plasma and Materials Processing, Department of Applied Physics, and NanoLab@TU/eEindhoven University of Technology, Postbus 513, 5600
MB Eindhoven, The Netherlands
| | - L. E. Black
- Institute for Photonic Integration, Photonic Integration, Department
of Electrical Engineering, Photonics and Semiconductor Nanophysics, Department
of Applied Physics, Plasma and Materials Processing, Department of Applied Physics, and NanoLab@TU/eEindhoven University of Technology, Postbus 513, 5600
MB Eindhoven, The Netherlands
| | - E. Smalbrugge
- Institute for Photonic Integration, Photonic Integration, Department
of Electrical Engineering, Photonics and Semiconductor Nanophysics, Department
of Applied Physics, Plasma and Materials Processing, Department of Applied Physics, and NanoLab@TU/eEindhoven University of Technology, Postbus 513, 5600
MB Eindhoven, The Netherlands
| | - P. J. van Veldhoven
- Institute for Photonic Integration, Photonic Integration, Department
of Electrical Engineering, Photonics and Semiconductor Nanophysics, Department
of Applied Physics, Plasma and Materials Processing, Department of Applied Physics, and NanoLab@TU/eEindhoven University of Technology, Postbus 513, 5600
MB Eindhoven, The Netherlands
| | - W. M. M. Kessels
- Institute for Photonic Integration, Photonic Integration, Department
of Electrical Engineering, Photonics and Semiconductor Nanophysics, Department
of Applied Physics, Plasma and Materials Processing, Department of Applied Physics, and NanoLab@TU/eEindhoven University of Technology, Postbus 513, 5600
MB Eindhoven, The Netherlands
| | - M. K. Smit
- Institute for Photonic Integration, Photonic Integration, Department
of Electrical Engineering, Photonics and Semiconductor Nanophysics, Department
of Applied Physics, Plasma and Materials Processing, Department of Applied Physics, and NanoLab@TU/eEindhoven University of Technology, Postbus 513, 5600
MB Eindhoven, The Netherlands
| | - A. Fiore
- Institute for Photonic Integration, Photonic Integration, Department
of Electrical Engineering, Photonics and Semiconductor Nanophysics, Department
of Applied Physics, Plasma and Materials Processing, Department of Applied Physics, and NanoLab@TU/eEindhoven University of Technology, Postbus 513, 5600
MB Eindhoven, The Netherlands
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23
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Baig SA, Boland JL, Damry DA, Tan HH, Jagadish C, Joyce HJ, Johnston MB. An Ultrafast Switchable Terahertz Polarization Modulator Based on III-V Semiconductor Nanowires. NANO LETTERS 2017; 17:2603-2610. [PMID: 28334532 DOI: 10.1021/acs.nanolett.7b00401] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Progress in the terahertz (THz) region of the electromagnetic spectrum is undergoing major advances, with advanced THz sources and detectors being developed at a rapid pace. Yet, ultrafast THz communication is still to be realized, owing to the lack of practical and effective THz modulators. Here, we present a novel ultrafast active THz polarization modulator based on GaAs semiconductor nanowires arranged in a wire-grid configuration. We utilize an optical pump-terahertz probe spectroscopy system and vary the polarization of the optical pump beam to demonstrate ultrafast THz modulation with a switching time of less than 5 ps and a modulation depth of -8 dB. We achieve an extinction of over 13% and a dynamic range of -9 dB, comparable to microsecond-switchable graphene- and metamaterial-based THz modulators, and surpassing the performance of optically switchable carbon nanotube THz polarizers. We show a broad bandwidth for THz modulation between 0.1 and 4 THz. Thus, this work presents the first THz modulator which combines not only a large modulation depth but also a broad bandwidth and picosecond time resolution for THz intensity and phase modulation, making it an ideal candidate for ultrafast THz communication.
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Affiliation(s)
- Sarwat A Baig
- Department of Engineering, University of Cambridge , 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Jessica L Boland
- Department of Physics, Clarendon Laboratory, University of Oxford , Parks Road, Oxford, OX1 3PU, United Kingdom
| | - Djamshid A Damry
- Department of Physics, Clarendon Laboratory, University of Oxford , Parks Road, Oxford, OX1 3PU, United Kingdom
| | - H Hoe Tan
- Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University , Canberra, Australian Capital Territory 2601, Australia
| | - Chennupati Jagadish
- Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University , Canberra, Australian Capital Territory 2601, Australia
| | - Hannah J Joyce
- Department of Engineering, University of Cambridge , 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Michael B Johnston
- Department of Physics, Clarendon Laboratory, University of Oxford , Parks Road, Oxford, OX1 3PU, United Kingdom
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24
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Li F, Li Z, Tan L, Zhou Y, Ma J, Lysevych M, Fu L, Tan HH, Jagadish C. Radiation effects on GaAs/AlGaAs core/shell ensemble nanowires and nanowire infrared photodetectors. NANOTECHNOLOGY 2017; 28:125702. [PMID: 28140378 DOI: 10.1088/1361-6528/aa5bad] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
With the recent advances in nanowire (NW) growth and fabrication, there has been rapid development and application of GaAs NWs in optoelectronics. It is also of importance to study the radiation tolerance of optoelectronic nano-devices for atomic energy and space-based applications. Here, photoluminescence (PL) and time-resolved photoluminescence measurements were carried out on GaAs/AlGaAs core/shell NWs at room temperature before and after 1 MeV proton irradiation with fluences ranging from 1.0 × 1012-3.0 × 1013 cm-2. It is found that the GaAs/AlGaAs core/shell NWs with smaller diameter show much less PL degradation compared with the ones with larger diameters. The increased radiation hardness is mainly attributed to the improvement of a room temperature dynamic-annealing mechanism near the surface of the NWs. We also found that the minority carrier lifetime is closely related to both the PL intensity and defect density induced by irradiation. Finally, GaAs/AlGaAs ensemble NW photodetectors operating in the near-infrared spectral regime have been demonstrated. The influence of proton irradiation on light and dark current characteristics also indicates that NW structures are a good potential candidate for radiation harsh-environment applications.
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Affiliation(s)
- Fajun Li
- National Key Laboratory of Tunable Laser Technology, Harbin Institute of Technology, Harbin 150001, People's Republic of China. Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra 2601, A.C.T., Australia
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25
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Kaveh M, Gao Q, Jagadish C, Ge J, Duscher G, Wagner HP. Controlling the exciton emission of gold coated GaAs-AlGaAs core-shell nanowires with an organic spacer layer. NANOTECHNOLOGY 2016; 27:485204. [PMID: 27811405 DOI: 10.1088/0957-4484/27/48/485204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Excitons are the most prominent optical excitations and controlling their emission is an important step towards new optical devices. We have investigated the exciton emission from uncoated and gold/aluminum quinoline (Alq3) coated GaAs-AlGaAs-GaAs core-shell nanowires (NWs) using temperature-, intensity- and polarization dependent photoluminescence (PL). Plasmonic GaAs-AlGaAs-GaAs NWs with a ∼10 nm thick Au coating but without an Alq3 spacer layer reveal a significant reduction of the PL intensity of the exciton emission compared with the uncoated NW sample. Plasmonic NW samples with the same nominal Au coverage and an additional Alq3 interlayer of 3 or 6 nm thickness show a clearly stronger PL intensity which increases with rising Alq3 spacer thickness. Time-resolved (TR) PL measurements reveal an increase of the exciton decay rate by a factor of up to two with decreasing Alq3 spacer thickness suggesting the presence of Förster energy transfer from NW excitons to plasmon oscillations in the gold film. The weak change of the decay time, however, indicates that Förster energy-transfer is only partially responsible for the PL quenching in the gold coated NWs. The main reason for the reduction of the PL emission is attributed to a gold induced band-bending in the GaAs NW core which causes exciton dissociation. With increasing Alq3 spacer thickness the band-bending decreases leading to a reduction of the exciton dissociation and PL quenching. Our interpretation is supported by electron energy loss spectroscopy measurements which show a signal reduction and blue shift of defect (possibly EL2) transitions when gold particles are deposited on NWs compared with bare or Alq3 coated NWs.
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Affiliation(s)
- M Kaveh
- Department of Physics and Astronomy, James Madison University, Harrisonburg, VA, USA
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26
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Cui Y, van Dam D, Mann SA, van Hoof NJJ, van Veldhoven PJ, Garnett EC, Bakkers EPAM, Haverkort JEM. Boosting Solar Cell Photovoltage via Nanophotonic Engineering. NANO LETTERS 2016; 16:6467-6471. [PMID: 27607337 DOI: 10.1021/acs.nanolett.6b02971] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Approaching the theoretically limiting open circuit voltage (Voc) of solar cells is crucial to optimize their photovoltaic performance. Here, we demonstrate experimentally that nanostructured layers can achieve a fundamentally larger Fermi level splitting, and thus a larger Voc, than planar layers. By etching tapered nanowires from planar indium phosphide (InP), we directly compare planar and nanophotonic geometries with the exact same material quality. We show that the external radiative efficiency of the nanostructured layer at 1 sun is increased by a factor 14 compared to the planar layer, leading to a 70 mV enhancement in Voc. The higher voltage arises from both the enhanced outcoupling of photons, which promotes radiative recombination, and the lower active material volume, which reduces bulk recombination. These effects are generic and promise to enhance the efficiency of current record planar solar cells made from other materials as well.
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Affiliation(s)
- Y Cui
- Applied Physics, Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - D van Dam
- Applied Physics, Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - S A Mann
- Center for Nanophotonics, FOM Institute AMOLF , 1098 XG Amsterdam, The Netherlands
| | - N J J van Hoof
- Applied Physics, Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - P J van Veldhoven
- Applied Physics, Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - E C Garnett
- Center for Nanophotonics, FOM Institute AMOLF , 1098 XG Amsterdam, The Netherlands
| | - E P A M Bakkers
- Applied Physics, Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands
| | - J E M Haverkort
- Applied Physics, Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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27
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Kinzel JB, Schülein FJR, Weiß M, Janker L, Bühler DD, Heigl M, Rudolph D, Morkötter S, Döblinger M, Bichler M, Abstreiter G, Finley JJ, Wixforth A, Koblmüller G, Krenner HJ. The Native Material Limit of Electron and Hole Mobilities in Semiconductor Nanowires. ACS NANO 2016; 10:4942-4953. [PMID: 27007813 DOI: 10.1021/acsnano.5b07639] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- Jörg B Kinzel
- Lehrstuhl für Experimentalphysik 1 and Augsburg Centre for Innovative Technologies (ACIT), Universität Augsburg , Universitätsstraße 1, 86159 Augsburg, Germany
- Nanosystems Initiative Munich (NIM) , Schellingstraße 4, 80339 München, Germany
| | - Florian J R Schülein
- Lehrstuhl für Experimentalphysik 1 and Augsburg Centre for Innovative Technologies (ACIT), Universität Augsburg , Universitätsstraße 1, 86159 Augsburg, Germany
- Nanosystems Initiative Munich (NIM) , Schellingstraße 4, 80339 München, Germany
| | - Matthias Weiß
- Lehrstuhl für Experimentalphysik 1 and Augsburg Centre for Innovative Technologies (ACIT), Universität Augsburg , Universitätsstraße 1, 86159 Augsburg, Germany
- Nanosystems Initiative Munich (NIM) , Schellingstraße 4, 80339 München, Germany
| | - Lisa Janker
- Lehrstuhl für Experimentalphysik 1 and Augsburg Centre for Innovative Technologies (ACIT), Universität Augsburg , Universitätsstraße 1, 86159 Augsburg, Germany
- Nanosystems Initiative Munich (NIM) , Schellingstraße 4, 80339 München, Germany
| | - Dominik D Bühler
- Lehrstuhl für Experimentalphysik 1 and Augsburg Centre for Innovative Technologies (ACIT), Universität Augsburg , Universitätsstraße 1, 86159 Augsburg, Germany
| | - Michael Heigl
- Lehrstuhl für Experimentalphysik 1 and Augsburg Centre for Innovative Technologies (ACIT), Universität Augsburg , Universitätsstraße 1, 86159 Augsburg, Germany
| | - Daniel Rudolph
- Nanosystems Initiative Munich (NIM) , Schellingstraße 4, 80339 München, Germany
- Walter Schottky Institut and Physik Department E24, Technische Universität München , Am Coulombwall 4, 85748 Garching, Germany
| | - Stefanie Morkötter
- Nanosystems Initiative Munich (NIM) , Schellingstraße 4, 80339 München, Germany
- Walter Schottky Institut and Physik Department E24, Technische Universität München , Am Coulombwall 4, 85748 Garching, Germany
| | - Markus Döblinger
- Department of Chemistry, Ludwig-Maximilians-Universität München , 81377 München, Germany
- Center for Nanoscience (CeNS), Ludwig-Maximilians-Universität München , Geschwister-Scholl-Platz 1, 80539 München, Germany
| | - Max Bichler
- Walter Schottky Institut and Physik Department E24, Technische Universität München , Am Coulombwall 4, 85748 Garching, Germany
| | - Gerhard Abstreiter
- Nanosystems Initiative Munich (NIM) , Schellingstraße 4, 80339 München, Germany
- Walter Schottky Institut and Physik Department E24, Technische Universität München , Am Coulombwall 4, 85748 Garching, Germany
- Institute for Advanced Study (IAS), Technische Universität München , Lichtenbergstraße 2a, 85748 Garching, Germany
| | - Jonathan J Finley
- Nanosystems Initiative Munich (NIM) , Schellingstraße 4, 80339 München, Germany
- Walter Schottky Institut and Physik Department E24, Technische Universität München , Am Coulombwall 4, 85748 Garching, Germany
| | - Achim Wixforth
- Lehrstuhl für Experimentalphysik 1 and Augsburg Centre for Innovative Technologies (ACIT), Universität Augsburg , Universitätsstraße 1, 86159 Augsburg, Germany
- Nanosystems Initiative Munich (NIM) , Schellingstraße 4, 80339 München, Germany
- Center for Nanoscience (CeNS), Ludwig-Maximilians-Universität München , Geschwister-Scholl-Platz 1, 80539 München, Germany
| | - Gregor Koblmüller
- Nanosystems Initiative Munich (NIM) , Schellingstraße 4, 80339 München, Germany
- Walter Schottky Institut and Physik Department E24, Technische Universität München , Am Coulombwall 4, 85748 Garching, Germany
| | - Hubert J Krenner
- Lehrstuhl für Experimentalphysik 1 and Augsburg Centre for Innovative Technologies (ACIT), Universität Augsburg , Universitätsstraße 1, 86159 Augsburg, Germany
- Nanosystems Initiative Munich (NIM) , Schellingstraße 4, 80339 München, Germany
- Center for Nanoscience (CeNS), Ludwig-Maximilians-Universität München , Geschwister-Scholl-Platz 1, 80539 München, Germany
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28
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Boland JL, Casadei A, Tütüncüoglu G, Matteini F, Davies CL, Jabeen F, Joyce HJ, Herz LM, Fontcuberta I Morral A, Johnston MB. Increased Photoconductivity Lifetime in GaAs Nanowires by Controlled n-Type and p-Type Doping. ACS NANO 2016; 10:4219-4227. [PMID: 26959350 DOI: 10.1021/acsnano.5b07579] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Controlled doping of GaAs nanowires is crucial for the development of nanowire-based electronic and optoelectronic devices. Here, we present a noncontact method based on time-resolved terahertz photoconductivity for assessing n- and p-type doping efficiency in nanowires. Using this technique, we measure extrinsic electron and hole concentrations in excess of 10(18) cm(-3) for GaAs nanowires with n-type and p-type doped shells. Furthermore, we show that controlled doping can significantly increase the photoconductivity lifetime of GaAs nanowires by over an order of magnitude: from 0.13 ns in undoped nanowires to 3.8 and 2.5 ns in n-doped and p-doped nanowires, respectively. Thus, controlled doping can be used to reduce the effects of parasitic surface recombination in optoelectronic nanowire devices, which is promising for nanowire devices, such as solar cells and nanowire lasers.
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Affiliation(s)
- Jessica L Boland
- Clarendon Laboratory, Department of Physics, University of Oxford , Parks Road, Oxford, OX1 3PU, United Kingdom
| | | | | | | | - Christopher L Davies
- Clarendon Laboratory, Department of Physics, University of Oxford , Parks Road, Oxford, OX1 3PU, United Kingdom
| | | | - Hannah J Joyce
- Department of Engineering, University of Cambridge , 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Laura M Herz
- Clarendon Laboratory, Department of Physics, University of Oxford , Parks Road, Oxford, OX1 3PU, United Kingdom
| | | | - Michael B Johnston
- Clarendon Laboratory, Department of Physics, University of Oxford , Parks Road, Oxford, OX1 3PU, United Kingdom
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29
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Zhao C, Ng TK, Prabaswara A, Conroy M, Jahangir S, Frost T, O'Connell J, Holmes JD, Parbrook PJ, Bhattacharya P, Ooi BS. An enhanced surface passivation effect in InGaN/GaN disk-in-nanowire light emitting diodes for mitigating Shockley-Read-Hall recombination. NANOSCALE 2015; 7:16658-16665. [PMID: 26242178 DOI: 10.1039/c5nr03448e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present a detailed study of the effects of dangling bond passivation and the comparison of different sulfide passivation processes on the properties of InGaN/GaN quantum-disk (Qdisk)-in-nanowire based light emitting diodes (NW-LEDs). Our results demonstrated the first organic sulfide passivation process for nitride nanowires (NWs). The results from Raman spectroscopy, photoluminescence (PL) measurements, and X-ray photoelectron spectroscopy (XPS) showed that octadecylthiol (ODT) effectively passivated the surface states, and altered the surface dynamic charge, and thereby recovered the band-edge emission. The effectiveness of the process with passivation duration was also studied. Moreover, we also compared the electro-optical performance of NW-LEDs emitting at green wavelength before and after ODT passivation. We have shown that the Shockley-Read-Hall (SRH) non-radiative recombination of NW-LEDs can be greatly reduced after passivation by ODT, which led to a much faster increasing trend of quantum efficiency and higher peak efficiency. Our results highlighted the possibility of employing this technique to further design and produce high performance NW-LEDs and NW-lasers.
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Affiliation(s)
- Chao Zhao
- Photonics Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
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30
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Morkötter S, Jeon N, Rudolph D, Loitsch B, Spirkoska D, Hoffmann E, Döblinger M, Matich S, Finley JJ, Lauhon LJ, Abstreiter G, Koblmüller G. Demonstration of Confined Electron Gas and Steep-Slope Behavior in Delta-Doped GaAs-AlGaAs Core-Shell Nanowire Transistors. NANO LETTERS 2015; 15:3295-302. [PMID: 25923841 DOI: 10.1021/acs.nanolett.5b00518] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Strong surface and impurity scattering in III-V semiconductor-based nanowires (NW) degrade the performance of electronic devices, requiring refined concepts for controlling charge carrier conductivity. Here, we demonstrate remote Si delta (δ)-doping of radial GaAs-AlGaAs core-shell NWs that unambiguously exhibit a strongly confined electron gas with enhanced low-temperature field-effect mobilities up to 5 × 10(3) cm(2) V(-1) s(-1). The spatial separation between the high-mobility free electron gas at the NW core-shell interface and the Si dopants in the shell is directly verified by atom probe tomographic (APT) analysis, band-profile calculations, and transport characterization in advanced field-effect transistor (FET) geometries, demonstrating powerful control over the free electron gas density and conductivity. Multigated NW-FETs allow us to spatially resolve channel width- and crystal phase-dependent variations in electron gas density and mobility along single NW-FETs. Notably, dc output and transfer characteristics of these n-type depletion mode NW-FETs reveal excellent drain current saturation and record low subthreshold slopes of 70 mV/dec at on/off ratios >10(4)-10(5) at room temperature.
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Affiliation(s)
- S Morkötter
- †Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany
| | - N Jeon
- ‡Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60201, United States
| | - D Rudolph
- †Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany
| | - B Loitsch
- †Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany
| | - D Spirkoska
- †Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany
| | - E Hoffmann
- †Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany
- ∥Institute for Advanced Study, Technische Universität München, Garching 85748, Germany
| | - M Döblinger
- §Department of Chemistry, Ludwig-Maximilians-Universität München, Munich 81377, Germany
| | - S Matich
- †Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany
| | - J J Finley
- †Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany
| | - L J Lauhon
- ‡Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60201, United States
| | - G Abstreiter
- †Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany
- ∥Institute for Advanced Study, Technische Universität München, Garching 85748, Germany
| | - G Koblmüller
- †Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany
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31
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Zhang G, Tateno K, Birowosuto MD, Notomi M, Sogawa T, Gotoh H. Controlled 1.1-1.6 μm luminescence in gold-free multi-stacked InAs/InP heterostructure nanowires. NANOTECHNOLOGY 2015; 26:115704. [PMID: 25712797 DOI: 10.1088/0957-4484/26/11/115704] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report controlled 1.1-1.6 μm luminescence in gold-free multi-stacked InAs/InP heterostructure nanowires (NWs). We realized the NWs by using an indium-particle-assisted vapor-liquid-solid synthesis approach. The growth temperature, as low as 320 °C, enables the formation of an atomically abrupt InP/InAs interface by supressing the diffusion and weakening the reservoir effect in the indium droplet. The low growth temperature also enables us to grow multi-stacked InAs/InP NWs in the axial direction without any growth on the NW side face. The high controllability of the growth technology ensures that the luminescence can be tailored by the thickness of InAs segment in InP NWs and cover the 1.3-1.5 μm telecommunication window range. By using the nanoscale-spatial-resolution technology combing cathodoluminescence with scanning electron microscopy, we directly correlated the site of different-thickness InAs segments with its luminescence property in a single NW and demonstrate the InAs-thickness-controlled energy of optical emission in 1.1-1.6 μm.
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Affiliation(s)
- Guoqiang Zhang
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa, 243-0198, Japan. NTT Nanophotonics Center, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa, 243-0198, Japan
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32
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Bussone G, Schäfer-Eberwein H, Dimakis E, Biermanns A, Carbone D, Tahraoui A, Geelhaar L, Bolívar PH, Schülli TU, Pietsch U. Correlation of electrical and structural properties of single as-grown GaAs nanowires on Si (111) substrates. NANO LETTERS 2015; 15:981-989. [PMID: 25631459 DOI: 10.1021/nl5037879] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present the results of the study of the correlation between the electrical and structural properties of individual GaAs nanowires measured in their as-grown geometry. The resistance and the effective charge carrier mobility were extracted for several nanowires, and subsequently, the same nano-objects were investigated using X-ray nanodiffraction. This revealed a number of perfectly stacked zincblende and twinned zincblende units separated by axial interfaces. Our results suggest a correlation between the electrical parameters and the number of intrinsic interfaces.
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33
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Boland JL, Conesa-Boj S, Parkinson P, Tütüncüoglu G, Matteini F, Rüffer D, Casadei A, Amaduzzi F, Jabeen F, Davies CL, Joyce HJ, Herz LM, Fontcuberta i Morral A, Johnston MB. Modulation doping of GaAs/AlGaAs core-shell nanowires with effective defect passivation and high electron mobility. NANO LETTERS 2015; 15:1336-1342. [PMID: 25602841 DOI: 10.1021/nl504566t] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Reliable doping is required to realize many devices based on semiconductor nanowires. Group III-V nanowires show great promise as elements of high-speed optoelectronic devices, but for such applications it is important that the electron mobility is not compromised by the inclusion of dopants. Here we show that GaAs nanowires can be n-type doped with negligible loss of electron mobility. Molecular beam epitaxy was used to fabricate modulation-doped GaAs nanowires with Al0.33Ga0.67As shells that contained a layer of Si dopants. We identify the presence of the doped layer from a high-angle annular dark field scanning electron microscopy cross-section image. The doping density, carrier mobility, and charge carrier lifetimes of these n-type nanowires and nominally undoped reference samples were determined using the noncontact method of optical pump terahertz probe spectroscopy. An n-type extrinsic carrier concentration of 1.10 ± 0.06 × 10(16) cm(-3) was extracted, demonstrating the effectiveness of modulation doping in GaAs nanowires. The room-temperature electron mobility was also found to be high at 2200 ± 300 cm(2) V(-1) s(-1) and importantly minimal degradation was observed compared with undoped reference nanowires at similar electron densities. In addition, modulation doping significantly enhanced the room-temperature photoconductivity and photoluminescence lifetimes to 3.9 ± 0.3 and 2.4 ± 0.1 ns respectively, revealing that modulation doping can passivate interfacial trap states.
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Affiliation(s)
- Jessica L Boland
- Department of Physics, University of Oxford , Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, United Kingdom
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