1
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Mediavilla I, Anaya J, Galiana B, Hrachowina L, Borgström MT, Jimenez J. A cathodoluminescence study of InP/InGaP axially heterostructured NWs for tandem solar cells. NANOTECHNOLOGY 2024; 35:195703. [PMID: 38316051 DOI: 10.1088/1361-6528/ad263d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 02/05/2024] [Indexed: 02/07/2024]
Abstract
Axially heterostructured nanowires (NWs) constitute a promising platform for advanced electronic and optoelectronic nanodevices. The presence of different materials in these NWs introduces a mismatch resulting in complex strain distributions susceptible of changing the band gap and carrier mobility. The growth of these NWs presents challenges related to the reservoir effect in the catalysts droplet that affect to the junction abruptness, and the occurrence of undesired lateral growth creating core-shell heterostructures that introduce additional strain. We present herein a cathodoluminescence (CL) analysis on axially heterostructured InP/InGaP NWs with tandem solar cell structure. The CL is complemented with micro Raman, micro photoluminescence (PL), and high resolution transmission electron microscopy measurements. The results reveal the zinc blende structure of the NWs, the presence of a thin InGaP shell around the InP bottom cell, along with its associated strain, and the doping distribution.
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Affiliation(s)
- I Mediavilla
- GdS Optronlab, Ed. LUCIA, Paseo de Belen 19, Universidad de Valladolid, E-47011, Valladolid, Spain
| | - J Anaya
- GdS Optronlab, Ed. LUCIA, Paseo de Belen 19, Universidad de Valladolid, E-47011, Valladolid, Spain
| | - B Galiana
- Universidad Carlos III de Madrid, Physics Department, Av. Universidad 40, Leganes, E-28911, Spain
| | - L Hrachowina
- Nano Lund and Division of Solid State Physics, Lund University, Box 118, SE-22100 Lund, Sweden
| | - M T Borgström
- Nano Lund and Division of Solid State Physics, Lund University, Box 118, SE-22100 Lund, Sweden
| | - J Jimenez
- GdS Optronlab, Ed. LUCIA, Paseo de Belen 19, Universidad de Valladolid, E-47011, Valladolid, Spain
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2
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Kolhep M, Pantle F, Karlinger M, Wang D, Scherer T, Kübel C, Stutzmann M, Zacharias M. Atomic Layer Deposition and Strain Analysis of Epitaxial GaN-ZnO Core-Shell Nanowires. NANO LETTERS 2023; 23:6920-6926. [PMID: 37499227 DOI: 10.1021/acs.nanolett.3c01531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
We demonstrate the epitaxial coating of GaN NWs with an epitaxial ZnO shell by atomic layer deposition at 300 °C. Scanning transmission electron microscopy proves a sharp and defect-free coherent interface. The strain in the core-shell structure due to the lattice mismatch and different thermal expansion coefficients of GaN and ZnO was analyzed using 4D-STEM strain mapping and Raman spectroscopy and compared to theoretical calculations. The results highlight the outstanding advantages of epitaxial shell growth using atomic layer deposition, e.g., conformal coating and precise thickness control.
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Affiliation(s)
- Maximilian Kolhep
- Laboratory for Nanotechnology, Department of Microsystems Engineering, University of Freiburg, Freiburg, 79110, Germany
| | - Florian Pantle
- Walter Schottky Institut and Physics Department, Technische Universität München, Garching, 85748, Germany
| | - Monika Karlinger
- Walter Schottky Institut and Physics Department, Technische Universität München, Garching, 85748, Germany
| | - Di Wang
- Karlsruhe Nano and Micro Facility (KNMF) and Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, 76344, Germany
| | - Torsten Scherer
- Karlsruhe Nano and Micro Facility (KNMF) and Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, 76344, Germany
| | - Christian Kübel
- Karlsruhe Nano and Micro Facility (KNMF) and Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, 76344, Germany
- Department of Materials and Earth Sciences, Technical University Darmstadt, Darmstadt, 64287, Germany
| | - Martin Stutzmann
- Walter Schottky Institut and Physics Department, Technische Universität München, Garching, 85748, Germany
| | - Margit Zacharias
- Laboratory for Nanotechnology, Department of Microsystems Engineering, University of Freiburg, Freiburg, 79110, Germany
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3
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Chen X, Alradhi H, Jin ZM, Zhu L, Sanchez AM, Ma S, Zhuang Q, Shao J. Mid-infrared photoluminescence revealing internal quantum efficiency enhancement of type-I and type-II InAs core/shell nanowires. OPTICS LETTERS 2022; 47:5208-5211. [PMID: 36181223 DOI: 10.1364/ol.473154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 09/12/2022] [Indexed: 06/16/2023]
Abstract
Internal quantum efficiency (IQE) is an important figure of merit for photoelectric applications. While the InAs core/shell (c/s) nanowire (NW) is a promising solution for efficient quantum emission, the relationship between the IQE and shell coating remains unclear. This Letter reports mid-infrared PL measurements on InAs/InGaAs, InAs/AlSb, and InAs/GaSb c/s NWs, together with bare InAs NWs as a reference. Analyses show that the IQE is depressed by a shell coating at 9 K but gets improved by up to approximately 50% for the InGaAs shell coating at 40 -140 K and up to approximately 20% beyond 110 K for the AlSb shell. The effect is ascribed not only to the crystal quality but more importantly to the radial band alignment. The result indicates the high-temperature IQE improvement of the type-I and type-II c/s NWs and the appropriateness of the mid-infrared PL analyses for narrow-gap NW evaluation.
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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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Küpers H, Lewis RB, Corfdir P, Niehle M, Flissikowski T, Grahn HT, Trampert A, Brandt O, Geelhaar L. Drastic Effect of Sequential Deposition Resulting from Flux Directionality on the Luminescence Efficiency of Nanowire Shells. ACS APPLIED MATERIALS & INTERFACES 2021; 13:50220-50227. [PMID: 34643384 DOI: 10.1021/acsami.1c12371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Core-shell nanowire heterostructures form the basis for many innovative devices. When compound nanowire shells are grown by directional deposition techniques, the azimuthal position of the sources for the different constituents in the growth reactor, substrate rotation, and nanowire self-shadowing inevitably lead to sequential deposition. Here, we uncover for In0.15Ga0.85As/GaAs shell quantum wells grown by molecular beam epitaxy a drastic impact of this sequentiality on the luminescence efficiency. The photoluminescence intensity of shell quantum wells grown with a flux sequence corresponding to migration enhanced epitaxy, that is, when As and the group-III metals essentially do not impinge at the same time, is more than 2 orders of magnitude higher than for shell quantum wells prepared with substantially overlapping fluxes. Transmission electron microscopy does not reveal any extended defects explaining this difference. Our analysis of photoluminescence transients shows that co-deposition has two detrimental microscopic effects. First, a higher density of electrically active point defects leads to internal electric fields reducing the electron-hole wave function overlap. Second, more point defects form that act as nonradiative recombination centers. Our study demonstrates that the source arrangement of the growth reactor, which is of mere technical relevance for planar structures, can have drastic consequences for the material properties of nanowire shells. We expect that this finding holds good also for other alloy nanowire shells.
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Affiliation(s)
- Hanno Küpers
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Ryan B Lewis
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Pierre Corfdir
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Michael Niehle
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Timur Flissikowski
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Holger T Grahn
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Achim Trampert
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Oliver Brandt
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Lutz Geelhaar
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, 10117 Berlin, Germany
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6
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Al Hassan A, Salehi WA, Lewis RB, Anjum T, Sternemann C, Geelhaar L, Pietsch U. Transition from elastic to plastic strain release in core-shell nanowires revealed by in-plane x-ray diffraction. NANOTECHNOLOGY 2021; 32:205705. [PMID: 33578397 DOI: 10.1088/1361-6528/abe5db] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We investigate the strain evolution and relaxation process as function of increasing lattice mismatch between the GaAs core and surrounding In x Ga1-x As shell in core-shell nanowire heterostructures grown on Si(111) substrates. The dimensions of the core and shell are kept constant whereas the indium concentration inside the shell is varied. Measuring the [Formula: see text] and [Formula: see text] in-plane Bragg reflections normal to the nanowire side edges and side facets, we observe a transition from elastic to plastic strain release for a shell indium content x > 0.5. Above the onset of plastic strain relaxation, indium rich mounds and an indium poor coherent shell grow simultaneously around the GaAs core. Mound formation was observed for indium contents x = 0.5 and 0.6 by scanning electron microscopy. Considering both the measured radial reflections and the axial 111 Bragg reflection, the 3D strain variation was extracted separately for the core and the In x Ga1-x As shell.
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Affiliation(s)
- Ali Al Hassan
- Naturwissenschaftlich-Technische Fakultät der Universität Siegen, D-57068 Siegen, Germany
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Waheed A Salehi
- Naturwissenschaftlich-Technische Fakultät der Universität Siegen, D-57068 Siegen, Germany
| | - Ryan B Lewis
- Department of Engineering Physics, McMaster University, Hamilton, Ontario L8S 4L7, Canada
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - Taseer Anjum
- Naturwissenschaftlich-Technische Fakultät der Universität Siegen, D-57068 Siegen, Germany
| | - Christian Sternemann
- Fakultät Physik/DELTA, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - Lutz Geelhaar
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - Ullrich Pietsch
- Naturwissenschaftlich-Technische Fakultät der Universität Siegen, D-57068 Siegen, Germany
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7
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Khayrudinov V, Remennyi M, Raj V, Alekseev P, Matveev B, Lipsanen H, Haggren T. Direct Growth of Light-Emitting III-V Nanowires on Flexible Plastic Substrates. ACS NANO 2020; 14:7484-7491. [PMID: 32437132 PMCID: PMC7315631 DOI: 10.1021/acsnano.0c03184] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 05/21/2020] [Indexed: 05/27/2023]
Abstract
Semiconductor nanowires are routinely grown on high-priced crystalline substrates as it is extremely challenging to grow directly on plastics and flexible substrates due to high-temperature requirements and substrate preparation. At the same time, plastic substrates can offer many advantages such as extremely low price, light weight, mechanical flexibility, shock and thermal resistance, and biocompatibility. We explore the direct growth of high-quality III-V nanowires on flexible plastic substrates by metal-organic vapor phase epitaxy (MOVPE). We synthesize InAs and InP nanowires on polyimide and show that the fabricated NWs are optically active with strong light emission in the mid-infrared range. We create a monolithic flexible nanowire-based p-n junction device on plastic in just two fabrication steps. Overall, we demonstrate that III-V nanowires can be synthesized directly on flexible plastic substrates inside a MOVPE reactor, and we believe that our results will further advance the development of the nanowire-based flexible electronic devices.
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Affiliation(s)
- Vladislav Khayrudinov
- Department
of Electronics and Nanoengineering, Micronova,
Aalto University, P.O. Box 13500, Espoo FI-00076, Finland
| | | | - Vidur Raj
- Department
of Electronic Materials Engineering, Research School of Physics and
Engineering, The Australian National University, Canberra, ACT 2601, Australia
| | | | | | - Harri Lipsanen
- Department
of Electronics and Nanoengineering, Micronova,
Aalto University, P.O. Box 13500, Espoo FI-00076, Finland
| | - Tuomas Haggren
- Department
of Electronics and Nanoengineering, Micronova,
Aalto University, P.O. Box 13500, Espoo FI-00076, Finland
- Department
of Electronic Materials Engineering, Research School of Physics and
Engineering, The Australian National University, Canberra, ACT 2601, Australia
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8
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Sumikura H, Zhang G, Takiguchi M, Takemura N, Shinya A, Gotoh H, Notomi M. Mid-Infrared Lasing of Single Wurtzite InAs Nanowire. NANO LETTERS 2019; 19:8059-8065. [PMID: 31638818 DOI: 10.1021/acs.nanolett.9b03249] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Mid-infrared (MIR) photonics is a developing technology for sensing materials by their characteristic MIR absorptions. Since silicon (Si) is a low-loss material in most of the MIR region, Si photonic structures have been fabricated to guide and confine MIR light, and they allow us to achieve sensitive and integrated sensing devices. However, since the implementation of MIR light sources on Si is still challenging, we propose a thick indium arsenide (InAs) nanowire as an MIR laser that can couple to Si photonic structures with material manipulation. In this study, thick InAs nanowires are grown on an indium phosphide substrate with a self-catalyst vapor-liquid-solid method and transferred to gold-deposited SiO2/Si substrates. Low-temperature microphotoluminescence (PL) spectroscopy shows that InAs nanowires exhibit broad PL peaking at a wavelength of around 2.6 μm (3850 cm-1 in frequency), which corresponds to the bandgap energy of wurtzite InAs. At high optical pump fluences, single InAs nanowire exhibits sharp emission peaks, while their integrated intensity and polarization degree increase abruptly at the threshold pump fluence. These nonlinear behaviors indicate that the MIR lasing action takes place in the InAs nanowire in its cavity mode. Our demonstration of the MIR nanowire laser expands the wavelength coverage and potential application of semiconductor nanowires.
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Affiliation(s)
- Hisashi Sumikura
- NTT Basic Research Laboratories , Nippon Telegraph and Telephone Corporation , Atsugi , Kanagawa 243-0198 , Japan
- Nanophotonics Center , Nippon Telegraph and Telephone Corporation , Atsugi , Kanagawa 243-0198 , Japan
| | - Guoqiang Zhang
- NTT Basic Research Laboratories , Nippon Telegraph and Telephone Corporation , Atsugi , Kanagawa 243-0198 , Japan
- Nanophotonics Center , Nippon Telegraph and Telephone Corporation , Atsugi , Kanagawa 243-0198 , Japan
| | - Masato Takiguchi
- NTT Basic Research Laboratories , Nippon Telegraph and Telephone Corporation , Atsugi , Kanagawa 243-0198 , Japan
- Nanophotonics Center , Nippon Telegraph and Telephone Corporation , Atsugi , Kanagawa 243-0198 , Japan
| | - Naotomo Takemura
- NTT Basic Research Laboratories , Nippon Telegraph and Telephone Corporation , Atsugi , Kanagawa 243-0198 , Japan
- Nanophotonics Center , Nippon Telegraph and Telephone Corporation , Atsugi , Kanagawa 243-0198 , Japan
| | - Akihiko Shinya
- NTT Basic Research Laboratories , Nippon Telegraph and Telephone Corporation , Atsugi , Kanagawa 243-0198 , Japan
- Nanophotonics Center , Nippon Telegraph and Telephone Corporation , Atsugi , Kanagawa 243-0198 , Japan
| | - Hideki Gotoh
- NTT Basic Research Laboratories , Nippon Telegraph and Telephone Corporation , Atsugi , Kanagawa 243-0198 , Japan
| | - Masaya Notomi
- NTT Basic Research Laboratories , Nippon Telegraph and Telephone Corporation , Atsugi , Kanagawa 243-0198 , Japan
- Nanophotonics Center , Nippon Telegraph and Telephone Corporation , Atsugi , Kanagawa 243-0198 , Japan
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9
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Li B, Li S, Sun Y, Li S, Chen G, Wang X. Enhanced luminescence properties of InAs nanowires via organic and inorganic sulfide passivation. NANOTECHNOLOGY 2019; 30:445704. [PMID: 31365914 DOI: 10.1088/1361-6528/ab3742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
InAs nanowires (NWs) have been considered to be highly suitable for future nanoscale photonic applications in mid-wave infrared region. However, progress in this area has been seriously hampered because of the poor radiative efficiency of InAs NWs attributed to their non-radiative (NR) surface. Herein, we demonstrated that a significant improvement of optical performances of InAs NWs grown by chemical vapor deposition could be achieved via sulfur passivation process. Luminescence properties of InAs NWs via organic sulfide (ODT) and inorganic sulfide ((NH4)2S) passivation were investigated by detailed photoluminescence (PL) measurement, which exhibited ∼17-fold enhancement in the intensity of optical emission compared to unpassivated InAs NWs. Moreover, the results of this investigation revealed that compared to ODT passivation, (NH4)2S passivation provided a more effective method to enhance the luminescence intensity even up to room temperature. This improvement of optical emission arises from the efficient passivation of surface defect states which act as competing NR centers. Furthermore, the stability of the passivated InAs NWs was investigated by PL measurement as a function of storage time in air. These findings are important for the successful implementation of optoelectronic devices based on InAs NWs.
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Affiliation(s)
- Baobao Li
- School of Materials Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, People's Republic of China
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10
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Balaghi L, Bussone G, Grifone R, Hübner R, Grenzer J, Ghorbani-Asl M, Krasheninnikov AV, Schneider H, Helm M, Dimakis E. Widely tunable GaAs bandgap via strain engineering in core/shell nanowires with large lattice mismatch. Nat Commun 2019; 10:2793. [PMID: 31243278 PMCID: PMC6595053 DOI: 10.1038/s41467-019-10654-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 05/20/2019] [Indexed: 11/09/2022] Open
Abstract
The realisation of photonic devices for different energy ranges demands materials with different bandgaps, sometimes even within the same device. The optimal solution in terms of integration, device performance and device economics would be a simple material system with widely tunable bandgap and compatible with the mainstream silicon technology. Here, we show that gallium arsenide nanowires grown epitaxially on silicon substrates exhibit a sizeable reduction of their bandgap by up to 40% when overgrown with lattice-mismatched indium gallium arsenide or indium aluminium arsenide shells. Specifically, we demonstrate that the gallium arsenide core sustains unusually large tensile strain with hydrostatic character and its magnitude can be engineered via the composition and the thickness of the shell. The resulted bandgap reduction renders gallium arsenide nanowires suitable for photonic devices across the near-infrared range, including telecom photonics at 1.3 and potentially 1.55 μm, with the additional possibility of monolithic integration in silicon-CMOS chips.
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Affiliation(s)
- Leila Balaghi
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328, Dresden, Germany
- Center for Advancing Electronics Dresden (cfaed), Technische Universität Dresden, 01062, Dresden, Germany
| | - Genziana Bussone
- PETRA III, Deutsches Elektronen-Synchrotron (DESY), 22607, Hamburg, Germany
| | - Raphael Grifone
- PETRA III, Deutsches Elektronen-Synchrotron (DESY), 22607, Hamburg, Germany
| | - René Hübner
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328, Dresden, Germany
| | - Jörg Grenzer
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328, Dresden, Germany
| | - Mahdi Ghorbani-Asl
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328, Dresden, Germany
| | - Arkady V Krasheninnikov
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328, Dresden, Germany
| | - Harald Schneider
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328, Dresden, Germany
| | - Manfred Helm
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328, Dresden, Germany
- Center for Advancing Electronics Dresden (cfaed), Technische Universität Dresden, 01062, Dresden, Germany
| | - Emmanouil Dimakis
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328, Dresden, Germany.
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11
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Ren D, Azizur-Rahman KM, Rong Z, Juang BC, Somasundaram S, Shahili M, Farrell AC, Williams BS, Huffaker DL. Room-Temperature Midwavelength Infrared InAsSb Nanowire Photodetector Arrays with Al 2O 3 Passivation. NANO LETTERS 2019; 19:2793-2802. [PMID: 30676752 DOI: 10.1021/acs.nanolett.8b04420] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Developing uncooled photodetectors at midwavelength infrared (MWIR) is critical for various applications including remote sensing, heat seeking, spectroscopy, and more. In this study, we demonstrate room-temperature operation of nanowire-based photodetectors at MWIR composed of vertical selective-area InAsSb nanowire photoabsorber arrays on large bandgap InP substrate with nanoscale plasmonic gratings. We accomplish this by significantly suppressing the nonradiative recombination at the InAsSb nanowire surfaces by introducing ex situ conformal Al2O3 passivation shells. Transient simulations estimate an extremely low surface recombination velocity on the order of 103 cm/s. We further achieve room-temperature photoluminescence emission from InAsSb nanowires, spanning the entire MWIR regime from 3 to 5 μm. A dry-etching process is developed to expose only the top nanowire facets for metal contacts, with the sidewalls conformally covered by Al2O3 shells, allowing for a higher internal quantum efficiency. Based on these techniques, we fabricate nanowire photodetectors with an optimized pitch and diameter and demonstrate room-temperature spectral response with MWIR detection signatures up to 3.4 μm. The results of this work indicate that uncooled focal plane arrays at MWIR on low-cost InP substrates can be designed with nanostructured absorbers for highly compact and fully integrated detection platforms.
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Affiliation(s)
- Dingkun Ren
- Department of Electrical and Computer Engineering , University of California, Los Angeles , Los Angeles , California 90095 , United States
| | - Khalifa M Azizur-Rahman
- School of Physics and Astronomy , Cardiff University , Cardiff , Wales CF24 3AA , United Kingdom
| | - Zixuan Rong
- Department of Electrical and Computer Engineering , University of California, Los Angeles , Los Angeles , California 90095 , United States
| | - Bor-Chau Juang
- Department of Electrical and Computer Engineering , University of California, Los Angeles , Los Angeles , California 90095 , United States
| | - Siddharth Somasundaram
- Department of Electrical and Computer Engineering , University of California, Los Angeles , Los Angeles , California 90095 , United States
| | - Mohammad Shahili
- Department of Electrical and Computer Engineering , University of California, Los Angeles , Los Angeles , California 90095 , United States
| | - Alan C Farrell
- Department of Electrical and Computer Engineering , University of California, Los Angeles , Los Angeles , California 90095 , United States
| | - Benjamin S Williams
- Department of Electrical and Computer Engineering , University of California, Los Angeles , Los Angeles , California 90095 , United States
- California NanoSystems Institute , University of California, Los Angeles , Los Angeles , California 90095 , United States
| | - Diana L Huffaker
- Department of Electrical and Computer Engineering , University of California, Los Angeles , Los Angeles , California 90095 , United States
- School of Physics and Astronomy , Cardiff University , Cardiff , Wales CF24 3AA , United Kingdom
- California NanoSystems Institute , University of California, Los Angeles , Los Angeles , California 90095 , United States
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12
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Göransson DJO, Borgström MT, Huang YQ, Messing ME, Hessman D, Buyanova IA, Chen WM, Xu HQ. Measurements of Strain and Bandgap of Coherently Epitaxially Grown Wurtzite InAsP-InP Core-Shell Nanowires. NANO LETTERS 2019; 19:2674-2681. [PMID: 30908918 DOI: 10.1021/acs.nanolett.9b00644] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We report on experimental determination of the strain and bandgap of InAsP in epitaxially grown InAsP-InP core-shell nanowires. The core-shell nanowires are grown via metal-organic vapor phase epitaxy. The as-grown nanowires are characterized by transmission electron microscopy, X-ray diffraction, micro-photoluminescence (μPL) spectroscopy, and micro-Raman (μ-Raman) spectroscopy measurements. We observe that the core-shell nanowires are of wurtzite (WZ) crystal phase and are coherently strained with the core and the shell having the same number of atomic planes in each nanowire. We determine the predominantly uniaxial strains formed in the core-shell nanowires along the nanowire growth axis and demonstrate that the strains can be described using an analytical expression. The bandgap energies in the strained WZ InAsP core materials are extracted from the μPL measurements of individual core-shell nanowires. The coherently strained core-shell nanowires demonstrated in this work offer the potentials for use in constructing novel optoelectronic devices and for development of piezoelectric photovoltaic devices.
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Affiliation(s)
- D J O Göransson
- NanoLund and Division of Solid State Physics , Lund University , Box 118, S-22100 Lund , Sweden
| | - M T Borgström
- NanoLund and Division of Solid State Physics , Lund University , Box 118, S-22100 Lund , Sweden
| | - Y Q Huang
- Department of Physics, Chemistry and Biology , Linköping University , S-581 83 Linköping , Sweden
| | - M E Messing
- NanoLund and Division of Solid State Physics , Lund University , Box 118, S-22100 Lund , Sweden
| | - D Hessman
- NanoLund and Division of Solid State Physics , Lund University , Box 118, S-22100 Lund , Sweden
| | - I A Buyanova
- Department of Physics, Chemistry and Biology , Linköping University , S-581 83 Linköping , Sweden
| | - W M Chen
- Department of Physics, Chemistry and Biology , Linköping University , S-581 83 Linköping , Sweden
| | - H Q Xu
- NanoLund and Division of Solid State Physics , Lund University , Box 118, S-22100 Lund , Sweden
- Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices, and Department of Electronics , Peking University , Beijing 100871 , China
- Beijing Academy of Quantum Information Sciences , West Bld. #3, No.10 Xibeiwang East Rd. , Haidian District, Beijing 100193 , China
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13
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Li X, Zhang K, Treu J, Stampfer L, Koblmueller G, Toor F, Prineas JP. Contactless Optical Characterization of Carrier Dynamics in Free-Standing InAs-InAlAs Core-Shell Nanowires on Silicon. NANO LETTERS 2019; 19:990-996. [PMID: 30620205 DOI: 10.1021/acs.nanolett.8b04226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Contactless time-resolved optical pump-probe and external quantum efficiency measurements were performed in epitaxially grown free-standing wurtzite indium arsenide/indium aluminum arsenide (InAs-InAlAs) core-shell nanowires on Si (111) substrate from 77 to 293 K. The first independent investigation of Shockley-Read-Hall, radiative, and Auger recombination in InAs-based NWs is presented. Although the Shockley-Read-Hall recombination coefficient was found to be at least 2 orders of magnitude larger than the average experimental values of other reported InAs materials, the Auger recombination coefficient was reported to be 10-fold smaller. The very low Auger and high radiative rates result in an estimated peak internal quantum efficiency of the core-shell nanowires as high as 22% at 77 K, making these nanowires of potential interest for high-efficiency mid-infrared emitters. A greater than 2-fold enhancement in minority carrier lifetime was observed from capping nanowires with a thin InAlAs shell due to the passivation of surface defects.
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Affiliation(s)
| | | | - Julian Treu
- Walter Schottky Institut and Physics Department , Technical University Munich , Garching 85748 , Germany
| | - Lukas Stampfer
- Walter Schottky Institut and Physics Department , Technical University Munich , Garching 85748 , Germany
| | - Gregor Koblmueller
- Walter Schottky Institut and Physics Department , Technical University Munich , Garching 85748 , Germany
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14
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Lancaster S, Groiss H, Zederbauer T, Andrews AM, MacFarland D, Schrenk W, Strasser G, Detz H. Suppression of axial growth by boron incorporation in GaAs nanowires grown by self-catalyzed molecular beam epitaxy. NANOTECHNOLOGY 2019; 30:065602. [PMID: 30523852 DOI: 10.1088/1361-6528/aaf11e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The addition of boron to GaAs nanowires grown by self-catalyzed molecular beam epitaxy was found to have a strong effect on the nanowire morphology, with axial growth greatly reduced as the nominal boron concentration was increased. Transmission electron microscopy measurements show that the Ga catalyst droplet was unintentionally consumed during growth. Concurrent radial growth, a rough surface morphology and tapering of nanowires grown under boron flux suggest that this droplet consumption is due to reduced Ga adatom diffusion on the nanowire sidewalls in the presence of boron. Modelling of the nanowire growth puts the diffusion length of Ga adatoms under boron flux at around 700-1000 nm. Analyses of the nanowire surfaces show regions of high boron concentration, indicating the surfactant nature of boron in GaAs.
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Affiliation(s)
- Suzanne Lancaster
- Center for Micro- and Nanostructures, Institute for Solid State Electronics, TU Wien, A-1040 Vienna, Austria
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15
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Zhang G, Takiguchi M, Tateno K, Tawara T, Notomi M, Gotoh H. Telecom-band lasing in single InP/InAs heterostructure nanowires at room temperature. SCIENCE ADVANCES 2019; 5:eaat8896. [PMID: 30801006 PMCID: PMC6386577 DOI: 10.1126/sciadv.aat8896] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 12/28/2018] [Indexed: 05/28/2023]
Abstract
Telecom-band single nanowire lasers made by the bottom-up vapor-liquid-solid approach, which is technologically important in optical fiber communication systems, still remain challenging. Here, we report telecom-band single nanowire lasers operating at room temperature based on multi-quantum-disk InP/InAs heterostructure nanowires. Transmission electron microscopy studies show that highly uniform multi-quantum-disk InP/InAs structure is grown in InP nanowires by self-catalyzed vapor-liquid-solid mode using indium particle catalysts. Optical excitation of individual nanowires yielded lasing in telecom band operating at room temperature. We show the tunability of laser wavelength range in telecom band by modulating the thickness of single InAs quantum disks through quantum confinement along the axial direction. The demonstration of telecom-band single nanowire lasers operating at room temperature is a major step forward in providing practical integrable coherent light sources for optoelectronics and data communication.
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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
| | - Masato Takiguchi
- 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
| | - Kouta Tateno
- 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
| | - Takehiko Tawara
- 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
| | - Masaya Notomi
- 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
| | - Hideki Gotoh
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
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16
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Ren D, Meng X, Rong Z, Cao M, Farrell AC, Somasundaram S, Azizur-Rahman KM, Williams BS, Huffaker DL. Uncooled Photodetector at Short-Wavelength Infrared Using InAs Nanowire Photoabsorbers on InP with p- n Heterojunctions. NANO LETTERS 2018; 18:7901-7908. [PMID: 30444964 DOI: 10.1021/acs.nanolett.8b03775] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In this work, we demonstrate an InAs nanowire photodetector at short-wavelength infrared (SWIR) composed of vertically oriented selective-area InAs nanowire photoabsorber arrays on InP substrates, forming InAs-InP heterojunctions. We measure a rectification ratio greater than 300 at room temperature, which indicates a desirable diode performance. The dark current density, normalized to the area of nanowire heterojunctions, is 130 mA/cm2 at a temperature of 300 K and a reverse bias of 0.5 V, making it comparable to the state-of-the-art bulk InAs p- i- n photodiodes. An analysis of the Arrhenius plot of the dark current at reverse bias yields an activation energy of 175 meV from 190 to 300 K, suggesting that the Shockley-Read-Hall (SRH) nonradiative current is the primary contributor to the dark current. By using three-dimensional electrical simulations, we determine that the SRH nonradiative current originates from the acceptor-like surface traps at the nanowire-passivation heterointerfaces. The spectral response at room temperature is also measured, with a clear photodetection signature observed at wavelengths up to 2.5 μm. This study provides an understanding of dark current for small band gap selective-area nanowires and paves the way to integrate these improved nanostructured photoabsorbers on large band gap substrates for high-performance photodetectors at SWIR.
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Affiliation(s)
- Dingkun Ren
- Department of Electrical and Computer Engineering , University of California, Los Angeles , Los Angeles , California 90095 , United States
| | - Xiao Meng
- School of Physics and Astronomy , Cardiff University , Cardiff , Wales CF24 3AA , United Kingdom
| | - Zixuan Rong
- Department of Electrical and Computer Engineering , University of California, Los Angeles , Los Angeles , California 90095 , United States
| | - Minh Cao
- Department of Electrical and Computer Engineering , University of California, Los Angeles , Los Angeles , California 90095 , United States
| | - Alan C Farrell
- Department of Electrical and Computer Engineering , University of California, Los Angeles , Los Angeles , California 90095 , United States
| | - Siddharth Somasundaram
- Department of Electrical and Computer Engineering , University of California, Los Angeles , Los Angeles , California 90095 , United States
| | - Khalifa M Azizur-Rahman
- School of Physics and Astronomy , Cardiff University , Cardiff , Wales CF24 3AA , United Kingdom
| | - Benjamin S Williams
- Department of Electrical and Computer Engineering , University of California, Los Angeles , Los Angeles , California 90095 , United States
- California NanoSystems Institute , University of California, Los Angeles , Los Angeles , California 90095 , United States
| | - Diana L Huffaker
- Department of Electrical and Computer Engineering , University of California, Los Angeles , Los Angeles , California 90095 , United States
- School of Physics and Astronomy , Cardiff University , Cardiff , Wales CF24 3AA , United Kingdom
- California NanoSystems Institute , University of California, Los Angeles , Los Angeles , California 90095 , United States
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17
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Ilyas N, Li D, Song Y, Zhong H, Jiang Y, Li W. Low-Dimensional Materials and State-of-the-Art Architectures for Infrared Photodetection. SENSORS (BASEL, SWITZERLAND) 2018; 18:E4163. [PMID: 30486432 PMCID: PMC6308609 DOI: 10.3390/s18124163] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 11/22/2018] [Accepted: 11/22/2018] [Indexed: 12/13/2022]
Abstract
Infrared photodetectors are gaining remarkable interest due to their widespread civil and military applications. Low-dimensional materials such as quantum dots, nanowires, and two-dimensional nanolayers are extensively employed for detecting ultraviolet to infrared lights. Moreover, in conjunction with plasmonic nanostructures and plasmonic waveguides, they exhibit appealing performance for practical applications, including sub-wavelength photon confinement, high response time, and functionalities. In this review, we have discussed recent advances and challenges in the prospective infrared photodetectors fabricated by low-dimensional nanostructured materials. In general, this review systematically summarizes the state-of-the-art device architectures, major developments, and future trends in infrared photodetection.
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Affiliation(s)
- Nasir Ilyas
- School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China.
| | - Dongyang Li
- School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China.
| | - Yuhao Song
- School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China.
| | - Hao Zhong
- School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China.
| | - Yadong Jiang
- School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China.
| | - Wei Li
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China.
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18
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Al Hassan A, Davtyan A, Küpers H, Lewis RB, Bahrami D, Bertram F, Bussone G, Richter C, Geelhaar L, Pietsch U. Complete structural and strain analysis of single GaAs/(In,Ga)As/GaAs core–shell–shell nanowires by means of in-plane and out-of-plane X-ray nanodiffraction. J Appl Crystallogr 2018. [DOI: 10.1107/s1600576718011287] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Typically, core–shell–shell semiconductor nanowires (NWs) made from III–V materials with low lattice mismatch grow pseudomorphically along the growth axis, i.e. the axial lattice parameters of the core and shell materials are the same. Therefore, both the structural composition and interface strain of the NWs are encoded along directions perpendicular to the growth axis. Owing to fluctuations in the supplied growth species during molecular beam epitaxy (MBE) growth, structural parameters such as local shell thickness, composition and strain may differ between NWs grown onto the same substrate. This requires structural analysis of single NWs instead of measuring NW ensembles. In this work, the complete structure of single GaAs/(In,Ga)As/GaAs core–shell–shell NW heterostructures is determined by means of X-ray nanodiffraction using synchrotron radiation. The NWs were grown by MBE on a prepatterned silicon (111) substrate with a core diameter of 50 nm and an (In,Ga)As shell thickness of 20 nm with a nominal indium concentration of 15%, capped by a 30 nm GaAs outer shell. In order to access single NWs with the X-ray nanobeam being incident parallel to the surface of the substrate, a single row of holes with a separation of 10 µm was defined by electron-beam lithography to act as nucleation centres for MBE NW growth. These well separated NWs were probed sequentially by X-ray nanodiffraction, recording three-dimensional reciprocal-space maps of Bragg reflections with scattering vectors parallel (out-of-plane) and perpendicular (in-plane) to the NW growth axis. From the out-of-plane 111 Bragg reflection, deviations from hexagonal symmetry were derived, together with the diameters of probed NWs grown under the same conditions. The radial NW composition and interface strain became accessible when measuring the two-dimensional scattering intensity distributions of the in-plane 2{\overline 2}0 and 22{\overline 4} reflections, exhibiting well pronounced thickness fringes perpendicular to the NW side planes (truncation rods, TRs). Quantitative values of thickness, composition and strain acting on the (In,Ga)As and GaAs shells were obtained via finite-element modelling of the core–shell–shell NWs and subsequent Fourier transform, simulating the TRs measured along the three different directions of the hexagonally shaped NWs simultaneously. Considering the experimental constraints of the current experiment, thicknesses and In content have been evaluated with uncertainties of ±2 nm and ±0.01, respectively. Comparing data taken from different single NWs, the shell thicknesses differ from one to another.
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19
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Ji X, Chen X, Yang X, Zhang X, Shao J, Yang T. Self-Seeded MOCVD Growth and Dramatically Enhanced Photoluminescence of InGaAs/InP Core-Shell Nanowires. NANOSCALE RESEARCH LETTERS 2018; 13:269. [PMID: 30187239 PMCID: PMC6125257 DOI: 10.1186/s11671-018-2690-3] [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: 03/28/2018] [Accepted: 08/28/2018] [Indexed: 06/08/2023]
Abstract
We report on the growth and characterization of InGaAs/InP core-shell nanowires on Si-(111) substrates by metal-organic chemical vapor deposition (MOCVD). The strain at the core-shell interface induced by the large lattice mismatch between the InGaAs core and InP shell materials has strong influence on the growth behavior of the InP shell, leading to the asymmetric growth of InP shell around the InGaAs core and even to the bending of the nanowires. Transmission electron microscopy (TEM) measurements reveal that the InP shell is coherent with the InGaAs core without any misfit dislocations. Furthermore, photoluminescence (PL) measurements at 77 K show that the PL peak intensity from the InGaAs/InP core-shell nanowires displays a ∼ 100 times enhancement compared to the only InGaAs core sample without InP shell due to the passivation of surface states and effective carrier confinement resulting from InP shell layer. The results obtained here further our understanding of the growth behavior of strained core-shell heterostructure nanowires and may open new possibilities for applications in InGaAs/InP heterostructure nanowire-based optoelectronic devices on Si platform.
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Affiliation(s)
- Xianghai Ji
- Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083 People’s Republic of China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
| | - Xiren Chen
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083 People’s Republic of China
| | - Xiaoguang Yang
- Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083 People’s Republic of China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
| | - Xingwang Zhang
- Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083 People’s Republic of China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
| | - Jun Shao
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083 People’s Republic of China
| | - Tao Yang
- Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083 People’s Republic of China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
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20
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Alhodaib A, Noori YJ, Carrington PJ, Sanchez AM, Thompson MD, Young RJ, Krier A, Marshall ARJ. Room-Temperature Mid-Infrared Emission from Faceted InAsSb Multi Quantum Wells Embedded in InAs Nanowires. NANO LETTERS 2018; 18:235-240. [PMID: 29191016 DOI: 10.1021/acs.nanolett.7b03977] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
There is considerable interest in the development of InAsSb-based nanowires for infrared photonics due to their high tunability across the infrared spectral range, high mobility, and integration with silicon electronics. However, optical emission is currently limited to low temperatures due to strong nonradiative Auger and surface recombination. Here, we present a new structure based on conical type II InAsSb/InAs multiquantum wells within InAs nanowires which exhibit bright mid-infrared photoluminescence up to room temperature. The nanowires are grown by catalyst-free selective area epitaxy on silicon. This unique geometry confines the electron-hole recombination to within the quantum wells which alleviates the problems associated with recombination via surface states, while the quantum confinement of carriers increases the radiative recombination rate and suppresses Auger recombination. This demonstration will pave the way for the development of new integrated quantum light sources operating in the technologically important mid-infrared spectral range.
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Affiliation(s)
- Aiyeshah Alhodaib
- Department of Physics, Lancaster University , Lancaster LA1 4YB, United Kingdom
- Department of Physics, Qassim University , Buryadh 51452, Saudi Arabia
| | - Yasir J Noori
- Department of Physics, Lancaster University , Lancaster LA1 4YB, United Kingdom
| | - Peter J Carrington
- Department of Engineering, Lancaster University , Lancaster LA1 4YW, United Kingdom
| | - Ana M Sanchez
- Department of Physics, University of Warwick , Coventry CV4 7AL, United Kingdom
| | - Michael D Thompson
- Department of Physics, Lancaster University , Lancaster LA1 4YB, United Kingdom
| | - Robert J Young
- Department of Physics, Lancaster University , Lancaster LA1 4YB, United Kingdom
| | - Anthony Krier
- Department of Physics, Lancaster University , Lancaster LA1 4YB, United Kingdom
| | - Andrew R J Marshall
- Department of Physics, Lancaster University , Lancaster LA1 4YB, United Kingdom
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21
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Möller M, Oliveira DS, Sahoo PK, Cotta MA, Iikawa F, Motisuke P, Molina-Sánchez A, de Lima MM, García-Cristóbal A, Cantarero A. Fermi energy dependence of the optical emission in core/shell InAs nanowire homostructures. NANOTECHNOLOGY 2017; 28:295702. [PMID: 28574403 DOI: 10.1088/1361-6528/aa76bf] [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
InAs nanowires grown by vapor-liquid-solid (VLS) method are investigated by photoluminescence. We observe that the Fermi energy of all samples is reduced by ∼20 meV when the size of the Au nanoparticle used for catalysis is increased from 5 to 20 nm. Additional capping with a thin InP shell enhances the optical emission and does not affect the Fermi energy. The unexpected behavior of the Fermi energy is attributed to the differences in the residual donor (likely carbon) incorporation in the axial (low) and lateral (high incorporation) growth in the VLS and vapor-solid (VS) methods, respectively. The different impurity incorporation rate in these two regions leads to a core/shell InAs homostructure. In this case, the minority carriers (holes) diffuse to the core due to the built-in electric field created by the radial impurity distribution. As a result, the optical emission is dominated by the core region rather than by the more heavily doped InAs shell. Thus, the photoluminescence spectra and the Fermi energy become sensitive to the core diameter. These results are corroborated by a theoretical model using a self-consistent method to calculate the radial carrier distribution and Fermi energy for distinct diameters of Au nanoparticles.
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Affiliation(s)
- M Möller
- Instituto de Física 'GlebWataghin', Unicamp, 13083-859, Campinas-SP, Brazil
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22
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Ren D, Farrell AC, Williams BS, Huffaker DL. Seeding layer assisted selective-area growth of As-rich InAsP nanowires on InP substrates. NANOSCALE 2017; 9:8220-8228. [PMID: 28580981 DOI: 10.1039/c7nr00948h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present the first demonstration of arsenic-rich InAs1-xPx (0 ≤ x ≤ 0.33) nanowire arrays grown on InP (111)B substrates by catalyst-free selective-area metal-organic chemical vapor deposition. It is shown that by introducing a thin InAs seeding layer prior to the growth of the nanowire, an extremely high vertical yield is achieved by eliminating rotational twins between (111)A and (111)B crystal orientations. InAsP nanowire arrays show strong emission of photoluminescence (PL) at room temperature, suggesting a significant reduction of surface state density compared with InAs nanowires. The phosphorus composition deduced from the PL peak energy is verified by energy-dispersive X-ray spectroscopy. The growth temperature shows a strong impact on the aspect ratio of InAs1-xPx nanowires with different phosphorus compositions. In addition, no PL emission is observed from nanowires grown with arsenic overpressure, likely due to an exchange of phosphorus with arsenic atoms at the surface which results in an increase in the surface state density. These results provide a path for the growth of heterojunctions based on As-rich InAs1-xPx for nanoscale short-wavelength infrared and mid-wavelength infrared optical devices.
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Affiliation(s)
- Dingkun Ren
- Department of Electrical Engineering, University of California at Los Angeles, Los Angeles, California 90095, USA.
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23
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Formation of GaAs/GaSb Core-Shell Heterostructured Nanowires Grown by Molecular-Beam Epitaxy. CRYSTALS 2017. [DOI: 10.3390/cryst7040094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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24
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Chen X, Zhuang Q, Alradhi H, Jin ZM, Zhu L, Chen X, Shao J. Midinfrared Photoluminescence up to 290 K Reveals Radiative Mechanisms and Substrate Doping-Type Effects of InAs Nanowires. NANO LETTERS 2017; 17:1545-1551. [PMID: 28231002 DOI: 10.1021/acs.nanolett.6b04629] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Photoluminescence (PL) as a conventional yet powerful optical spectroscopy may provide crucial insight into the mechanism of carrier recombination and bandedge structure in semiconductors. In this study, mid-infrared PL measurements on vertically aligned InAs nanowires (NWs) are realized for the first time in a wide temperature range of up to 290 K, by which the radiative recombinations are clarified in the NWs grown on n- and p-type Si substrates, respectively. A dominant PL feature is identified to be from the type-II optical transition across the interfaces between the zinc-blend (ZB) and the wurtzite (WZ) InAs, a lower-energy feature at low temperatures is ascribed to impurity-related transition, and a higher-energy feature at high temperatures originates in the interband transition of the WZ InAs being activated by thermal-induced electron transfer. The optical properties of the ZB-on-WZ and WZ-on-ZB interfaces are asymmetric, and stronger nonradiative recombination and weaker carrier-phonon interaction show up in the NWs on p-type substrate in which built-in electric field forms and leads to carrier assembling around the WZ-on-ZB interface. The results indicate that wide temperature-range infrared PL analysis can serve as efficient vehicle for clarifying optical properties and bandedge processes of the crystal-phase interfaces in vertically aligned InAs NWs.
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Affiliation(s)
- Xiren Chen
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences , 200083 Shanghai, China
| | - Qiandong Zhuang
- Physics Department, Lancaster University , LA14YB Lancaster, United Kingdom
| | - H Alradhi
- Physics Department, Lancaster University , LA14YB Lancaster, United Kingdom
| | - Zh M Jin
- Physics Department, Lancaster University , LA14YB Lancaster, United Kingdom
| | - Liangqing Zhu
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences , 200083 Shanghai, China
- Key Laboratory of Polar Materials and Devices, East China Normal University , 200062 Shanghai, China
| | - Xin Chen
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences , 200083 Shanghai, China
| | - Jun Shao
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences , 200083 Shanghai, China
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25
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Speckbacher M, Treu J, Whittles TJ, Linhart WM, Xu X, Saller K, Dhanak VR, Abstreiter G, Finley JJ, Veal TD, Koblmüller G. Direct Measurements of Fermi Level Pinning at the Surface of Intrinsically n-Type InGaAs Nanowires. NANO LETTERS 2016; 16:5135-42. [PMID: 27458736 DOI: 10.1021/acs.nanolett.6b02061] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Surface effects strongly dominate the intrinsic properties of semiconductor nanowires (NWs), an observation that is commonly attributed to the presence of surface states and their modification of the electronic band structure. Although the effects of the exposed, bare NW surface have been widely studied with respect to charge carrier transport and optical properties, the underlying electronic band structure, Fermi level pinning, and surface band bending profiles are not well explored. Here, we directly and quantitatively assess the Fermi level pinning at the surfaces of composition-tunable, intrinsically n-type InGaAs NWs, as one of the prominent, technologically most relevant NW systems, by using correlated photoluminescence (PL) and X-ray photoemission spectroscopy (XPS). From the PL spectral response, we reveal two dominant radiative recombination pathways, that is, direct near-band edge transitions and red-shifted, spatially indirect transitions induced by surface band bending. The separation of their relative transition energies changes with alloy composition by up to more than ∼40 meV and represent a direct measure for the amount of surface band bending. We further extract quantitatively the Fermi level to surface valence band maximum separation using XPS, and directly verify a composition-dependent transition from downward to upward band bending (surface electron accumulation to depletion) with increasing Ga-content x(Ga) at a crossover near x(Ga) ∼ 0.2. Core level spectra further demonstrate the nature of extrinsic surface states being caused by In-rich suboxides arising from the native oxide layer at the InGaAs NW surface.
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Affiliation(s)
- Maximilian Speckbacher
- Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
| | - Julian Treu
- Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
| | - Thomas J Whittles
- Stephenson Institute for Renewable Energy and Department of Physics, University of Liverpool , Liverpool L69 7ZF, United Kingdom
| | - Wojciech M Linhart
- Stephenson Institute for Renewable Energy and Department of Physics, University of Liverpool , Liverpool L69 7ZF, United Kingdom
| | - Xiaomo Xu
- Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
| | - Kai Saller
- Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
| | - Vinod R Dhanak
- Stephenson Institute for Renewable Energy and Department of Physics, University of Liverpool , Liverpool L69 7ZF, United Kingdom
| | - Gerhard Abstreiter
- Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
| | - Jonathan J Finley
- Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
| | - Tim D Veal
- Stephenson Institute for Renewable Energy and Department of Physics, University of Liverpool , Liverpool L69 7ZF, United Kingdom
| | - Gregor Koblmüller
- Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
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26
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Ji X, Yang X, Du W, Pan H, Luo S, Ji H, Xu HQ, Yang T. InAs/GaSb core-shell nanowires grown on Si substrates by metal-organic chemical vapor deposition. NANOTECHNOLOGY 2016; 27:275601. [PMID: 27232079 DOI: 10.1088/0957-4484/27/27/275601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report the growth of InAs/GaSb core-shell heterostructure nanowires with smooth sidewalls on Si substrates using metal-organic chemical vapor deposition with no assistance from foreign catalysts. Sb adatoms were observed to strongly influence the morphology of the GaSb shell. In particular, Ga droplets form on the nanowire tips when a relatively low TMSb flow rate is used, whereas the droplets are missing and the radial growth of the GaSb is enhanced due to a reduction in the diffusion length of the Ga adatoms when the TMSb flow rate is increased. Moreover, transmission electron microscopy measurements revealed that the GaSb shell coherently grew on the InAs core. The results obtained here show that the InAs/GaSb core-shell nanowires grown using the Si platform have strong potential in the fabrication of future nanometer-scale devices and in the study of fundamental quantum physics.
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Affiliation(s)
- Xianghai Ji
- Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, PO Box 912, Beijing 100083, People's Republic of China
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27
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Fang X, Wei Z, Yang Y, Chen R, Li Y, Tang J, Fang D, Jia H, Wang D, Fan J, Ma X, Yao B, Wang X. Ultraviolet Electroluminescence from ZnS@ZnO Core-Shell Nanowires/p-GaN Introduced by Exciton Localization. ACS APPLIED MATERIALS & INTERFACES 2016; 8:1661-1666. [PMID: 26710654 DOI: 10.1021/acsami.5b08961] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We investigate the electroluminescence (EL) from light emitting diodes (LEDs) of ZnO nanowires/p-GaN structure and ZnS@ZnO core-shell nanowires/p-GaN structure. With the increase of forward bias, the emission peak of ZnO nanowires/p-GaN structure heterojunction shows a blue-shift, while the ZnS@ZnO core-shell nanowires/p-GaN structure demonstrates a changing EL emission; the ultraviolet (UV) emission at 378 nm can be observed. This discrepancy is related to the localized states introduced by ZnS particles, which results in a different carrier recombination process near the interfaces of the heterojunction. The localized states capture the carriers in ZnO nanowires and convert them to localized excitons under high forward bias. A strong UV emission due to localized excitons can be observed. Our results indicated that utilizing localized excitons should be a new route toward ZnO-based ultraviolet LEDs with high efficiency.
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Affiliation(s)
- Xuan Fang
- State Key Laboratory of High Power Semiconductor Lasers, School of Science, Changchun University of Science and Technology , 7089 Wei-Xing Road, Changchun 130022, P. R. China
| | - Zhipeng Wei
- State Key Laboratory of High Power Semiconductor Lasers, School of Science, Changchun University of Science and Technology , 7089 Wei-Xing Road, Changchun 130022, P. R. China
| | - Yahui Yang
- Department of Electrical and Electronic Engineering, South University of Science and Technology of China , Shenzhen, Guangdong 518055, P. R. China
| | - Rui Chen
- Department of Electrical and Electronic Engineering, South University of Science and Technology of China , Shenzhen, Guangdong 518055, P. R. China
| | - Yongfeng Li
- Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education, College of Physics, JilinUniversity , Changchun 130012, P. R. China
| | - Jilong Tang
- State Key Laboratory of High Power Semiconductor Lasers, School of Science, Changchun University of Science and Technology , 7089 Wei-Xing Road, Changchun 130022, P. R. China
| | - Dan Fang
- State Key Laboratory of High Power Semiconductor Lasers, School of Science, Changchun University of Science and Technology , 7089 Wei-Xing Road, Changchun 130022, P. R. China
| | - Huimin Jia
- State Key Laboratory of High Power Semiconductor Lasers, School of Science, Changchun University of Science and Technology , 7089 Wei-Xing Road, Changchun 130022, P. R. China
| | - Dengkui Wang
- State Key Laboratory of High Power Semiconductor Lasers, School of Science, Changchun University of Science and Technology , 7089 Wei-Xing Road, Changchun 130022, P. R. China
| | - Jie Fan
- State Key Laboratory of High Power Semiconductor Lasers, School of Science, Changchun University of Science and Technology , 7089 Wei-Xing Road, Changchun 130022, P. R. China
| | - Xiaohui Ma
- State Key Laboratory of High Power Semiconductor Lasers, School of Science, Changchun University of Science and Technology , 7089 Wei-Xing Road, Changchun 130022, P. R. China
| | - Bin Yao
- Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education, College of Physics, JilinUniversity , Changchun 130012, P. R. China
| | - Xiaohua Wang
- State Key Laboratory of High Power Semiconductor Lasers, School of Science, Changchun University of Science and Technology , 7089 Wei-Xing Road, Changchun 130022, P. R. China
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28
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Mayer B, Janker L, Loitsch B, Treu J, Kostenbader T, Lichtmannecker S, Reichert T, Morkötter S, Kaniber M, Abstreiter G, Gies C, Koblmüller G, Finley JJ. Monolithically Integrated High-β Nanowire Lasers on Silicon. NANO LETTERS 2016; 16:152-6. [PMID: 26618638 DOI: 10.1021/acs.nanolett.5b03404] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Reliable technologies for the monolithic integration of lasers onto silicon represent the holy grail for chip-level optical interconnects. In this context, nanowires (NWs) fabricated using III-V semiconductors are of strong interest since they can be grown site-selectively on silicon using conventional epitaxial approaches. Their unique one-dimensional structure and high refractive index naturally facilitate low loss optical waveguiding and optical recirculation in the active NW-core region. However, lasing from NWs on silicon has not been achieved to date, due to the poor modal reflectivity at the NW-silicon interface. We demonstrate how, by inserting a tailored dielectric interlayer at the NW-Si interface, low-threshold single mode lasing can be achieved in vertical-cavity GaAs-AlGaAs core-shell NW lasers on silicon as measured at low temperature. By exploring the output characteristics along a detection direction parallel to the NW-axis, we measure very high spontaneous emission factors comparable to nanocavity lasers (β = 0.2) and achieve ultralow threshold pump energies ≤11 pJ/pulse. Analysis of the input-output characteristics of the NW lasers and the power dependence of the lasing emission line width demonstrate the potential for high pulsation rates ≥250 GHz. Such highly efficient nanolasers grown monolithically on silicon are highly promising for the realization of chip-level optical interconnects.
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Affiliation(s)
- B Mayer
- Walter Schottky Institut and Physik Department, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
| | - L Janker
- Walter Schottky Institut and Physik Department, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
| | - B Loitsch
- Walter Schottky Institut and Physik Department, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
| | - J Treu
- Walter Schottky Institut and Physik Department, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
| | - T Kostenbader
- Walter Schottky Institut and Physik Department, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
| | - S Lichtmannecker
- Walter Schottky Institut and Physik Department, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
| | - T Reichert
- Walter Schottky Institut and Physik Department, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
| | - S Morkötter
- Walter Schottky Institut and Physik Department, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
| | - M Kaniber
- Walter Schottky Institut and Physik Department, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
| | - G Abstreiter
- Institute of Advanced Study, Technische Universität München , Lichtenbergstraße 2a, 85748 Garching, Germany
| | - C Gies
- Institute for Theoretical Physics, University of Bremen , 28334 Bremen, Germany
| | - G Koblmüller
- Walter Schottky Institut and Physik Department, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
| | - J J Finley
- Walter Schottky Institut and Physik Department, Technische Universität München , Am Coulombwall 4, Garching 85748, Germany
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29
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Treu J, Stettner T, Watzinger M, Morkötter S, Döblinger M, Matich S, Saller K, Bichler M, Abstreiter G, Finley JJ, Stangl J, Koblmüller G. Lattice-Matched InGaAs-InAlAs Core-Shell Nanowires with Improved Luminescence and Photoresponse Properties. NANO LETTERS 2015; 15:3533-40. [PMID: 25922974 PMCID: PMC4434527 DOI: 10.1021/acs.nanolett.5b00979] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 04/23/2015] [Indexed: 05/25/2023]
Abstract
Core-shell nanowires (NW) have become very prominent systems for band engineered NW heterostructures that effectively suppress detrimental surface states and improve performance of related devices. This concept is particularly attractive for material systems with high intrinsic surface state densities, such as the low-bandgap In-containing group-III arsenides, however selection of inappropriate, lattice-mismatched shell materials have frequently caused undesired strain accumulation, defect formation, and modifications of the electronic band structure. Here, we demonstrate the realization of closely lattice-matched radial InGaAs-InAlAs core-shell NWs tunable over large compositional ranges [x(Ga)∼y(Al) = 0.2-0.65] via completely catalyst-free selective-area molecular beam epitaxy. On the basis of high-resolution X-ray reciprocal space maps the strain in the NW core is found to be insignificant (ε < 0.1%), which is further reflected by the absence of strain-induced spectral shifts in luminescence spectra and nearly unmodified band structure. Remarkably, the lattice-matched InAlAs shell strongly enhances the optical efficiency by up to 2 orders of magnitude, where the efficiency enhancement scales directly with increasing band offset as both Ga- and Al-contents increase. Ultimately, we fabricated vertical InGaAs-InAlAs NW/Si photovoltaic cells and show that the enhanced internal quantum efficiency is directly translated to an energy conversion efficiency that is ∼3-4 times larger as compared to an unpassivated cell. These results highlight the promising performance of lattice-matched III-V core-shell NW heterostructures with significant impact on future development of related nanophotonic and electronic devices.
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Affiliation(s)
- Julian Treu
- Walter Schottky Institut, Physik Department, and Center
of Nanotechnology and Nanomaterials, Technische
Universität München, Am Coulombwall 4, Garching, 85748, Germany
- Nanosystems Initiative
Munich (NIM), Schellingstrasse
4, München, 80799, Germany
| | - Thomas Stettner
- Walter Schottky Institut, Physik Department, and Center
of Nanotechnology and Nanomaterials, Technische
Universität München, Am Coulombwall 4, Garching, 85748, Germany
| | - Marc Watzinger
- Institute of Semiconductor and Solid State
Physics, Johannes Kepler University Linz, Altenbergerstrasse 69, Linz, 4040, Austria
| | - Stefanie Morkötter
- Walter Schottky Institut, Physik Department, and Center
of Nanotechnology and Nanomaterials, Technische
Universität München, Am Coulombwall 4, Garching, 85748, Germany
| | - Markus Döblinger
- Deparment of Chemistry, Ludwig-Maximilian
Universität München, Butenandtstrasse 5-13, München, 81377, Germany
| | - Sonja Matich
- Walter Schottky Institut, Physik Department, and Center
of Nanotechnology and Nanomaterials, Technische
Universität München, Am Coulombwall 4, Garching, 85748, Germany
| | - Kai Saller
- Walter Schottky Institut, Physik Department, and Center
of Nanotechnology and Nanomaterials, Technische
Universität München, Am Coulombwall 4, Garching, 85748, Germany
| | - Max Bichler
- Walter Schottky Institut, Physik Department, and Center
of Nanotechnology and Nanomaterials, Technische
Universität München, Am Coulombwall 4, Garching, 85748, Germany
| | - Gerhard Abstreiter
- Walter Schottky Institut, Physik Department, and Center
of Nanotechnology and Nanomaterials, Technische
Universität München, Am Coulombwall 4, Garching, 85748, Germany
- Nanosystems Initiative
Munich (NIM), Schellingstrasse
4, München, 80799, Germany
- Institute
for Advanced Study, Technische Universität
München, Lichtenbergstraße
2a, Garching, 85748, Germany
| | - Jonathan J. Finley
- Walter Schottky Institut, Physik Department, and Center
of Nanotechnology and Nanomaterials, Technische
Universität München, Am Coulombwall 4, Garching, 85748, Germany
- Nanosystems Initiative
Munich (NIM), Schellingstrasse
4, München, 80799, Germany
| | - Julian Stangl
- Institute of Semiconductor and Solid State
Physics, Johannes Kepler University Linz, Altenbergerstrasse 69, Linz, 4040, Austria
| | - Gregor Koblmüller
- Walter Schottky Institut, Physik Department, and Center
of Nanotechnology and Nanomaterials, Technische
Universität München, Am Coulombwall 4, Garching, 85748, Germany
- Nanosystems Initiative
Munich (NIM), Schellingstrasse
4, München, 80799, Germany
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30
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Rieger T, Grützmacher D, Lepsa MI. Misfit dislocation free InAs/GaSb core-shell nanowires grown by molecular beam epitaxy. NANOSCALE 2015; 7:356-364. [PMID: 25406991 DOI: 10.1039/c4nr05164e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this report, we present the growth and structural analyses of broken gap InAs/GaSb core-shell nanowires by molecular beam epitaxy using an Au-free approach. Depending on the shell growth temperature, two distinct growth regimes for the GaSb shells are identified resulting in conformal or tapered shells. Morphological analyses reveal a dodecagonal nanowire cross-section after GaSb shell growth. Detailed transmission electron microscope investigations from different zone axes confirm that the small lattice mismatch of 0.6% allows the deposition of 40 nm thick GaSb shells free of misfit dislocations. Additionally, an abrupt interface from InAs to GaSb is found. These nanowires are suitable for future devices such as TFETs.
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Affiliation(s)
- T Rieger
- Peter Grünberg Institut 9 and JARA-FIT, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
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31
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Li Q, Yuan Y, Chen Z, Jin X, Wei TH, Li Y, Qin Y, Sun W. Core-shell nanophosphor architecture: toward efficient energy transport in inorganic/organic hybrid solar cells. ACS APPLIED MATERIALS & INTERFACES 2014; 6:12798-12807. [PMID: 24967836 DOI: 10.1021/am5027709] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In this work, a core-shell nanostructure of samarium phosphates encapsulated into a Eu(3+)-doped silica shell has been successfully fabricated, which has been confirmed by X-ray diffraction, transmission electron microscopy (TEM), and high-resolution TEM. Moreover, we report the energy transfer process from the Sm(3+) to emitters Eu(3+) that widens the light absorption range of the hybrid solar cells (HSCs) and the strong enhancement of the electron-transport of TiO2/poly(3-hexylthiophene) (P3HT) bulk heterojunction (BHJ) HSCs by introducing the unique core-shell nanoarchitecture. Furthermore, by applying femtosecond transient absorption spectroscopy, we successfully obtain the electron transport lifetimes of BHJ systems with or without incorporating the core-shell nanophosphors (NPs). Concrete evidence has been provided that the doping of core-shell NPs improves the efficiency of electron transfers from donor to acceptor, but the hole transport almost remains unchanged. In particular, the hot electron transfer lifetime was shortened from 30.2 to 16.7 ps, i.e., more than 44% faster than pure TiO2 acceptor. Consequently, a notable power conversion efficiency of 3.30% for SmPO4@Eu(3+):SiO2 blended TiO2/P3HT HSCs is achieved at 5 wt % as compared to 1.98% of pure TiO2/P3HT HSCs. This work indicates that the core-shell NPs can efficiently broaden the absorption region, facilitate electron-transport of BHJ, and enhance photovoltaic performance of inorganic/organic HSCs.
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Affiliation(s)
- Qinghua Li
- Key Laboratory of Jiangxi Province for Persistant Pollutants Control and Resources Recycle, Nanchang Hangkong University , Nanchang, 330063, P. R. China
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32
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Arlauskas A, Treu J, Saller K, Beleckaitė I, Koblmüller G, Krotkus A. Strong terahertz emission and its origin from catalyst-free InAs nanowire arrays. NANO LETTERS 2014; 14:1508-1514. [PMID: 24502812 DOI: 10.1021/nl404737r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The unique features of nanowires (NW), such as the high aspect ratio and extensive surface area, are expected to play a key role in the development of very efficient semiconductor surface emitters in the terahertz (THz) spectral range. Here, we report on optically excited THz emission from catalyst-free grown arrays of intrinsically n-type InAs NWs using THz time-domain spectroscopy. Depending on the aspect ratio, the THz emission efficiency of the n-type InAs NWs is found to be up to ∼3 times stronger than that of bulk p-type InAs, known as currently the most efficient semiconductor-based THz surface emitter. Characteristic differences from bulk p-type InAs are particularly revealed from excitation wavelength-dependent measurements, showing monotonously increasing THz pulse amplitude in the NW arrays with increasing photon energy. Further polarization-dependent and two-color pump-probe experiments elucidate the physical mechanism of the THz emission: In contrast to bulk p-type InAs, where the anisotropic photoconductivity in the surface electric field is the dominant cause for THz pulse generation, the origin of the intrinsic THz emission in the NWs is based on the photo-Dember effect. The strong THz emission from high aspect ratio NW arrays further suggests an improved out-coupling of the radiation, while further enhancements in efficiency using core-shell NW geometries are discussed.
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Affiliation(s)
- Andrius Arlauskas
- Center for Physical Sciences and Technology , 01180, A. Goštauto 11, Vilnius, Lithuania
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