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Olszewski K, Sobanska M, Dubrovskii VG, Leshchenko ED, Wierzbicka A, Zytkiewicz ZR. Geometrical Selection of GaN Nanowires Grown by Plasma-Assisted MBE on Polycrystalline ZrN Layers. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2587. [PMID: 37764616 PMCID: PMC10537475 DOI: 10.3390/nano13182587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 09/13/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023]
Abstract
GaN nanowires grown on metal substrates have attracted increasing interest for a wide range of applications. Herein, we report GaN nanowires grown by plasma-assisted molecular beam epitaxy on thin polycrystalline ZrN buffer layers, sputtered onto Si(111) substrates. The nanowire orientation was studied by X-ray diffraction and scanning electron microscopy, and then described within a model as a function of the Ga beam angle, nanowire tilt angle, and substrate rotation. We show that vertically aligned nanowires grow faster than inclined nanowires, which leads to an interesting effect of geometrical selection of the nanowire orientation in the directional molecular beam epitaxy technique. After a given growth time, this effect depends on the nanowire surface density. At low density, the nanowires continue to grow with random orientations as nucleated. At high density, the effect of preferential growth induced by the unidirectional supply of the material in MBE starts to dominate. Faster growing nanowires with smaller tilt angles shadow more inclined nanowires that grow slower. This helps to obtain more regular ensembles of vertically oriented GaN nanowires despite their random position induced by the metallic grains at nucleation. The obtained dense ensembles of vertically aligned GaN nanowires on ZrN/Si(111) surfaces are highly relevant for device applications. Importantly, our results are not specific for GaN nanowires on ZrN buffers, and should be relevant for any nanowires that are epitaxially linked to the randomly oriented surface grains in the directional molecular beam epitaxy.
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Affiliation(s)
- Karol Olszewski
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland (Z.R.Z.)
| | - Marta Sobanska
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland (Z.R.Z.)
| | - Vladimir G. Dubrovskii
- Faculty of Physics, St. Petersburg State University, Universitetskaya Embankment 13V, 199034 St. Petersburg, Russia; (V.G.D.)
| | - Egor D. Leshchenko
- Faculty of Physics, St. Petersburg State University, Universitetskaya Embankment 13V, 199034 St. Petersburg, Russia; (V.G.D.)
| | - Aleksandra Wierzbicka
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland (Z.R.Z.)
| | - Zbigniew R. Zytkiewicz
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland (Z.R.Z.)
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2
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Khalilian M, Bi Z, Johansson J, Lenrick F, Hultin O, Colvin J, Timm R, Wallenberg R, Ohlsson J, Pistol ME, Gustafsson A, Samuelson L. Dislocation-Free and Atomically Flat GaN Hexagonal Microprisms for Device Applications. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1907364. [PMID: 32578387 DOI: 10.1002/smll.201907364] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 04/28/2020] [Indexed: 05/12/2023]
Abstract
III-nitrides are considered the material of choice for light-emitting diodes (LEDs) and lasers in the visible to ultraviolet spectral range. The development is hampered by lattice and thermal mismatch between the nitride layers and the growth substrate leading to high dislocation densities. In order to overcome the issue, efforts have gone into selected area growth of nanowires (NWs), using their small footprint in the substrate to grow virtually dislocation-free material. Their geometry is defined by six tall side-facets and a pointed tip which limits the design of optoelectronic devices. Growth of dislocation-free and atomically smooth 3D hexagonal GaN micro-prisms with a flat, micrometer-sized top-surface is presented. These self-forming structures are suitable for optical devices such as low-loss optical cavities for high-efficiency LEDs. The structures are made by annealing GaN NWs with a thick radial shell, reforming them into hexagonal flat-top prisms with six equivalents either m- or s-facets depending on the initial heights of the top pyramid and m-facets of the NWs. This shape is kinetically controlled and the reformation can be explained with a phenomenological model based on Wulff construction that have been developed. It is expected that the results will inspire further research into micron-sized III-nitride-based devices.
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Affiliation(s)
- Maryam Khalilian
- Solid State Physics and NanoLund, Lund University, Box 118, Lund, 221 00, Sweden
| | - Zhaoxia Bi
- Solid State Physics and NanoLund, Lund University, Box 118, Lund, 221 00, Sweden
| | - Jonas Johansson
- Solid State Physics and NanoLund, Lund University, Box 118, Lund, 221 00, Sweden
| | - Filip Lenrick
- nCHREM/Centre for Analysis and Synthesis and NanoLund, Lund University, Box 124, Lund, 221 00, Sweden
| | - Olof Hultin
- Solid State Physics and NanoLund, Lund University, Box 118, Lund, 221 00, Sweden
| | - Jovana Colvin
- Synchrotron Radiation Research and NanoLund, Lund University, Box 118, Lund, 221 00, Sweden
| | - Rainer Timm
- Synchrotron Radiation Research and NanoLund, Lund University, Box 118, Lund, 221 00, Sweden
| | - Reine Wallenberg
- nCHREM/Centre for Analysis and Synthesis and NanoLund, Lund University, Box 124, Lund, 221 00, Sweden
| | - Jonas Ohlsson
- Solid State Physics and NanoLund, Lund University, Box 118, Lund, 221 00, Sweden
| | - Mats-Erik Pistol
- Solid State Physics and NanoLund, Lund University, Box 118, Lund, 221 00, Sweden
| | - Anders Gustafsson
- Solid State Physics and NanoLund, Lund University, Box 118, Lund, 221 00, Sweden
| | - Lars Samuelson
- Solid State Physics and NanoLund, Lund University, Box 118, Lund, 221 00, Sweden
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Sobanska M, Zytkiewicz ZR, Klosek K, Kruszka R, Golaszewska K, Ekielski M, Gieraltowska S. Selective area formation of GaN nanowires on GaN substrates by the use of amorphous Al x O y nucleation layer. NANOTECHNOLOGY 2020; 31:184001. [PMID: 31940593 DOI: 10.1088/1361-6528/ab6bf2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Examples are presented that application of amorphous Al x O y nucleation layer is an efficient way of controlling spatial distribution of GaN nanowires grown by plasma-assisted molecular beam epitaxy. On GaN/sapphire substrates Al x O y stripes induce formation of GaN nanowires while a compact GaN layer is formed outside the stripes. We show that the ratio of nanowire length h to the thickness of the compact layer d can be tailored by adjusting impinging gallium and nitrogen fluxes. Calculations of the h/d aspect ratio were performed taking into account dependence of nanowire incubation time on the growth parameters. In agreement with calculations we found that the value of h/d ratio can be increased by increasing the N/Ga flux ratio in the way that the N-limited growth regime determines nanowire axial growth rate while growth of compact layer remains Ga-limited. This ensures the highest value of the h/d aspect ratio. Local modification of GaN growth kinetics caused by surface diffusion of Ga adatoms through the boundary separating the Al x O y stripe and the GaN/sapphire substrate is discussed. We show that during the nanowire incubation period gallium is transported out of the Al x O y stripe, which delays nanowire nucleation onset and leads to reduced length of GaN nanowires in the vicinity of the stripe edge. Simultaneously the growth on the GaN/sapphire substrate is locally enhanced, so the planar GaN layers adopts a typical edge shape of mesa structures grown by selective area growth. Ga diffusion length on a-Al x O y surface of ∼500 nm is inferred from our results.
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Affiliation(s)
- Marta Sobanska
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Zbigniew R Zytkiewicz
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Kamil Klosek
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Renata Kruszka
- Institute of Electron Technology, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | | | - Marek Ekielski
- Institute of Electron Technology, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Sylwia Gieraltowska
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
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Review of GaN Thin Film and Nanorod Growth Using Magnetron Sputter Epitaxy. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10093050] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Magnetron sputter epitaxy (MSE) offers several advantages compared to alternative GaN epitaxy growth methods, including mature sputtering technology, the possibility for very large area deposition, and low-temperature growth of high-quality electronic-grade GaN. In this article, we review the basics of reactive sputtering for MSE growth of GaN using a liquid Ga target. Various target biasing schemes are discussed, including direct current (DC), radio frequency (RF), pulsed DC, and high-power impulse magnetron sputtering (HiPIMS). Examples are given for MSE-grown GaN thin films with material quality comparable to those grown using alternative methods such as molecular-beam epitaxy (MBE), metal–organic chemical vapor deposition (MOCVD), and hydride vapor phase epitaxy (HVPE). In addition, successful GaN doping and the fabrication of practical devices have been demonstrated. Beyond the planar thin film form, MSE-grown GaN nanorods have also been demonstrated through self-assembled and selective area growth (SAG) method. With better understanding in process physics and improvements in material quality, MSE is expected to become an important technology for the growth of GaN.
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AlGaN Nanowires for Ultraviolet Light-Emitting: Recent Progress, Challenges, and Prospects. MICROMACHINES 2020; 11:mi11020125. [PMID: 31979274 PMCID: PMC7074201 DOI: 10.3390/mi11020125] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 01/19/2020] [Accepted: 01/22/2020] [Indexed: 12/12/2022]
Abstract
In this paper, we discuss the recent progress made in aluminum gallium nitride (AlGaN) nanowire ultraviolet (UV) light-emitting diodes (LEDs). The AlGaN nanowires used for such LED devices are mainly grown by molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD); and various foreign substrates/templates have been investigated. Devices on Si so far exhibit the best performance, whereas devices on metal and graphene have also been investigated to mitigate various limitations of Si substrate, e.g., the UV light absorption. Moreover, patterned growth techniques have also been developed to grow AlGaN nanowire UV LED structures, in order to address issues with the spontaneously formed nanowires. Furthermore, to reduce the quantum confined Stark effect (QCSE), nonpolar AlGaN nanowire UV LEDs exploiting the nonpolar nanowire sidewalls have been demonstrated. With these recent developments, the prospects, together with the general challenges of AlGaN nanowire UV LEDs, are discussed in the end.
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Sobanska M, Zytkiewicz ZR, Calabrese G, Geelhaar L, Fernández-Garrido S. Comprehensive analysis of the self-assembled formation of GaN nanowires on amorphous Al x O y : in situ quadrupole mass spectrometry studies. NANOTECHNOLOGY 2019; 30:154002. [PMID: 30641512 DOI: 10.1088/1361-6528/aafe17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A comprehensive description of the self-assembled formation of GaN nanowires (NWs) by plasma-assisted molecular beam epitaxy (PAMBE) on amorphous-Al x O y buffered Si is presented. The incubation time that precedes the formation of GaN NWs is analyzed as a function of the growth parameters using line-of-sight quadrupole mass spectrometry. We found that the incubation time follows an Arrhenius-type temperature dependence as well as an inverse power law with respect to the Ga flux. Our results reveal a weaker dependence of the incubation time on the Ga flux and faster nucleation on amorphous-Al x O y in comparison to conventional nitridated Si substrates. In addition, an unprecedented analysis of the dependence of the incubation time on the N flux demonstrates a stronger dependence of the incubation time on the N than on the Ga flux. Our results are summarized in growth diagrams to visualize the impact of the growth parameters on the incubation time. The diagrams can also be used to predict the incubation time for so far unexplored growth conditions. Finally, we measured the desorbing Ga flux upon the nucleation stage to determine the growth parameters that result in effective N-rich conditions as required for the self-assembled formation of GaN NWs. These original measurements were combined with the knowledge gained on the incubation time to create a growth map that illustrates the different growth regimes that can be obtained when GaN is grown on an amorphous-Al x O y buffer layer, regardless of the host substrate. Such a map provides a useful guide to induce the growth and control the morphology of GaN NW ensembles on amorphous-Al x O y . Results presented in this work allow to conclude that amorphous-Al x O y is preferred over nitridated Si as it enables shorter incubation times as well as a wider range of growth parameters to induce the self-assembled formation of GaN NWs in PAMBE.
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Affiliation(s)
- M Sobanska
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
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7
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Zhao S, Wang R, Chu S, Mi Z. Molecular Beam Epitaxy of III-Nitride Nanowires: Emerging Applications From Deep-Ultraviolet Light Emitters and Micro-LEDs to Artificial Photosynthesis. IEEE NANOTECHNOLOGY MAGAZINE 2019. [DOI: 10.1109/mnano.2019.2891370] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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8
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May BJ, Belz MR, Ahamed A, Sarwar ATMG, Selcu CM, Myers RC. Nanoscale Electronic Conditioning for Improvement of Nanowire Light-Emitting-Diode Efficiency. ACS NANO 2018; 12:3551-3556. [PMID: 29641896 DOI: 10.1021/acsnano.8b00538] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Commercial III-Nitride LEDs and lasers spanning visible and ultraviolet wavelengths are based on epitaxial films. Alternatively, nanowire-based III-Nitride optoelectronics offer the advantage of strain compliance and high crystalline quality growth on a variety of inexpensive substrates. However, nanowire LEDs exhibit an inherent property distribution, resulting in uneven current spreading through macroscopic devices that consist of millions of individual nanowire diodes connected in parallel. Despite being electrically connected, only a small fraction of nanowires, sometimes <1%, contribute to the electroluminescence (EL). Here, we show that a population of electrical shorts exists in the devices, consisting of a subset of low-resistance nanowires that pass a large portion of the total current in the ensemble devices. Burn-in electronic conditioning is performed by applying a short-term overload voltage; the nanoshorts experience very high current density, sufficient to render them open circuits, thereby forcing a new current path through more nanowire LEDs in an ensemble device. Current-voltage measurements of individual nanowires are acquired using conductive atomic force microscopy to observe the removal of nanoshorts using burn-in. In macroscopic devices, this results in a 33× increase in peak EL and reduced leakage current. Burn-in conditioning of nanowire ensembles therefore provides a straightforward method to mitigate nonuniformities inherent to nanowire devices.
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Affiliation(s)
- Brelon J May
- Department of Materials Science and Engineering , The Ohio State University , Columbus , Ohio 43210 , United States
| | - Matthew R Belz
- Department of Electrical and Computer Engineering , The Ohio State University , Columbus , Ohio 43210 , United States
| | - Arshad Ahamed
- Department of Physics , The Ohio State University , Columbus , Ohio 43210 , United States
| | - A T M G Sarwar
- Department of Electrical and Computer Engineering , The Ohio State University , Columbus , Ohio 43210 , United States
| | - Camelia M Selcu
- Department of Physics , The Ohio State University , Columbus , Ohio 43210 , United States
| | - Roberto C Myers
- Department of Materials Science and Engineering , The Ohio State University , Columbus , Ohio 43210 , United States
- Department of Electrical and Computer Engineering , The Ohio State University , Columbus , Ohio 43210 , United States
- Department of Physics , The Ohio State University , Columbus , Ohio 43210 , United States
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Prabaswara A, Min JW, Zhao C, Janjua B, Zhang D, Albadri AM, Alyamani AY, Ng TK, Ooi BS. Direct Growth of III-Nitride Nanowire-Based Yellow Light-Emitting Diode on Amorphous Quartz Using Thin Ti Interlayer. NANOSCALE RESEARCH LETTERS 2018; 13:41. [PMID: 29411164 PMCID: PMC5801136 DOI: 10.1186/s11671-018-2453-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Accepted: 01/23/2018] [Indexed: 05/30/2023]
Abstract
Consumer electronics have increasingly relied on ultra-thin glass screen due to its transparency, scalability, and cost. In particular, display technology relies on integrating light-emitting diodes with display panel as a source for backlighting. In this study, we undertook the challenge of integrating light emitters onto amorphous quartz by demonstrating the direct growth and fabrication of a III-nitride nanowire-based light-emitting diode. The proof-of-concept device exhibits a low turn-on voltage of 2.6 V, on an amorphous quartz substrate. We achieved ~ 40% transparency across the visible wavelength while maintaining electrical conductivity by employing a TiN/Ti interlayer on quartz as a translucent conducting layer. The nanowire-on-quartz LED emits a broad linewidth spectrum of light centered at true yellow color (~ 590 nm), an important wavelength bridging the green-gap in solid-state lighting technology, with significantly less strain and dislocations compared to conventional planar quantum well nitride structures. Our endeavor highlighted the feasibility of fabricating III-nitride optoelectronic device on a scalable amorphous substrate through facile growth and fabrication steps. For practical demonstration, we demonstrated tunable correlated color temperature white light, leveraging on the broadly tunable nanowire spectral characteristics across red-amber-yellow color regime.
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Affiliation(s)
- Aditya Prabaswara
- Photonics Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900 Saudi Arabia
| | - Jung-Wook Min
- Photonics Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900 Saudi Arabia
| | - Chao Zhao
- Photonics Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900 Saudi Arabia
| | - Bilal Janjua
- Photonics Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900 Saudi Arabia
| | - Daliang Zhang
- Imaging and Characterization Core Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900 Saudi Arabia
| | - Abdulrahman M. Albadri
- National Center for Nanotechnology, King Abdulaziz City for Science and Technology (KACST), Riyadh, 11442-6086 Saudi Arabia
| | - Ahmed Y. Alyamani
- National Center for Nanotechnology, King Abdulaziz City for Science and Technology (KACST), Riyadh, 11442-6086 Saudi Arabia
| | - Tien Khee Ng
- Photonics Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900 Saudi Arabia
| | - Boon S. Ooi
- Photonics Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900 Saudi Arabia
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Song W, Wang R, Wang X, Guo D, Chen H, Zhu Y, Liu L, Zhou Y, Sun Q, Wang L, Li S. a-Axis GaN/AlN/AlGaN Core-Shell Heterojunction Microwires as Normally Off High Electron Mobility Transistors. ACS APPLIED MATERIALS & INTERFACES 2017; 9:41435-41442. [PMID: 29111660 DOI: 10.1021/acsami.7b12986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Micro/nanowire-based devices have been envisioned as a promising new route toward improved electronic and optoelectronic applications, which attracts considerable research interests. However, suffering from applicable strategies to synthesize uniform core-shell structures to meet the requirement for the investigations of electrical transport behaviors along the length direction or high electron mobility transistor (HEMT) devices, heterojunction wire-based electronics have been explored limitedly. In the present work, GaN/AlN/AlGaN core-shell heterojunction microwires on patterned Si substrates were synthesized without any catalyst via metalorganic chemical vapor deposition. The as-synthesized microwires had low dislocation, sharp, and uniform heterojunction interfaces. Electrical transport performances were evaluated by fabricating HEMTs on the heterojunction microwire channels. Results demonstrated that a normally off operation was achieved with a threshold voltage of 1.4 V, a high on/off current ratio of 108, a transconductance of 165 mS/mm, and a low subthreshold swing of 81 mV/dec. The normally off operation may attribute to the weak polarization along semipolar facets of the heterojunction, which leads to weak constrain of 2DEG.
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Affiliation(s)
- Weidong Song
- Guangdong Engineering Research Center of Optoelectronic Functional Materials and Devices, South China Normal University , Guangzhou 510631, P. R. China
| | - Rupeng Wang
- Guangdong Engineering Research Center of Optoelectronic Functional Materials and Devices, South China Normal University , Guangzhou 510631, P. R. China
| | - Xingfu Wang
- Guangdong Engineering Research Center of Optoelectronic Functional Materials and Devices, South China Normal University , Guangzhou 510631, P. R. China
| | - Dexiao Guo
- Guangdong Engineering Research Center of Optoelectronic Functional Materials and Devices, South China Normal University , Guangzhou 510631, P. R. China
| | - Hang Chen
- Guangdong Engineering Research Center of Optoelectronic Functional Materials and Devices, South China Normal University , Guangzhou 510631, P. R. China
| | - Yuntao Zhu
- Guangdong Engineering Research Center of Optoelectronic Functional Materials and Devices, South China Normal University , Guangzhou 510631, P. R. China
| | - Liu Liu
- Guangdong Engineering Research Center of Optoelectronic Functional Materials and Devices, South China Normal University , Guangzhou 510631, P. R. China
| | - Yu Zhou
- Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences , Suzhou 215123, P. R. China
| | - Qian Sun
- Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences , Suzhou 215123, P. R. China
| | - Li Wang
- School of Materials Science and Engineering, Nanchang University , Nanchang 330031, P. R. China
| | - Shuti Li
- Guangdong Engineering Research Center of Optoelectronic Functional Materials and Devices, South China Normal University , Guangzhou 510631, P. R. China
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Xu Z, Yu Y, Han J, Wen L, Gao F, Zhang S, Li G. The mechanism of indium-assisted growth of (In)GaN nanorods: eliminating nanorod coalescence by indium-enhanced atomic migration. NANOSCALE 2017; 9:16864-16870. [PMID: 29075717 DOI: 10.1039/c7nr04555g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Both well vertically aligned and uniformly separated (In)GaN nanorods (NRs) were successfully grown on Si(111) substrates by plasma-assisted molecular beam epitaxy. Effects of supplied indium (In) flux on the morphology of (In)GaN NRs were investigated systematically. The scanning electron microscopic analysis and transmission electron microscopic measurements revealed that the presence of In flux can help to inhibit NR coalescence and obtain well-separated (In)GaN NRs. By increasing the supplied In flux, the densities of (In)GaN NRs decreased and the axial growth rates increased. According to the energy dispersive X-ray spectrometry measurements and theoretical calculations, the increase of In content of the NRs enhanced Ga diffusion on the NR sidewalls, which resulted in an increased axial growth rate. A kinetic In-assisted growth model for the well-separated (In)GaN NRs is therefore proposed. The model explains that the presence of In flux not only reduces the density of (In)GaN NRs due to the increase in substrate surface migration of Ga adatoms at nucleation stage but also lead to a remarkable enhancement of axial growth rate at growth stage. Consequently, the NR coalescence was significantly suppressed. The results provide a demonstration of obtaining well-separated (In)GaN NRs and open up further possibility of developing (In)GaN NR-based optoelectronic devices.
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Affiliation(s)
- Zhenzhu Xu
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
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12
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Rajan Philip M, Choudhary DD, Djavid M, Bhuyian MN, Bui THQ, Misra D, Khreishah A, Piao J, Nguyen HD, Le KQ, Nguyen HPT. Fabrication of Phosphor-Free III-Nitride Nanowire Light-Emitting Diodes on Metal Substrates for Flexible Photonics. ACS OMEGA 2017; 2:5708-5714. [PMID: 31457831 PMCID: PMC6644652 DOI: 10.1021/acsomega.7b00843] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 08/29/2017] [Indexed: 05/29/2023]
Abstract
In this paper, we report our study on high-performance III-nitride nanowire light-emitting diodes (LEDs) on copper (Cu) substrates via the substrate-transfer process. Nanowire LED structures were first grown on silicon-on-insulator (SOI) substrates by molecular beam epitaxy. Subsequently, the SOI substrate was removed by combining dry- and wet-etching processes. Compared to conventional nanowire LEDs on Si, the nanowire LEDs on Cu exhibit several advantages, including more efficient thermal management and enhanced light-extraction efficiency (LEE) because of the usage of metal reflectors and highly thermally conductive metal substrates. The LED on Cu, therefore, has stronger photoluminescence, electroluminescence intensities, and better current-voltage characteristics compared to the conventional nanowire LED on Si. Our simulation results further confirm the improved device performance of LEDs on Cu, compared to LEDs on Si. The LEE of the nanowire LED on Cu is nine times higher than that of the LED on Si at the same nanowire radius of 60 nm and spacing of 130 nm. Moreover, by engineering the device-active region, we achieved high-brightness phosphor-free LEDs on Cu with highly stable white-light emission and high color-rendering index of ∼95, showing their promising applications in general lighting, flexible displays, and wearable applications.
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Affiliation(s)
- Moab Rajan Philip
- Department
of Electrical and Computer Engineering and Electronic Imaging Center, New Jersey Institute of Technology, 323 Martin Luther King Boulevard, University Heights, Newark, New Jersey 07102, United States
| | - Dipayan Datta Choudhary
- Department
of Electrical and Computer Engineering and Electronic Imaging Center, New Jersey Institute of Technology, 323 Martin Luther King Boulevard, University Heights, Newark, New Jersey 07102, United States
| | - Mehrdad Djavid
- Department
of Electrical and Computer Engineering and Electronic Imaging Center, New Jersey Institute of Technology, 323 Martin Luther King Boulevard, University Heights, Newark, New Jersey 07102, United States
| | - Md Nasiruddin Bhuyian
- Department
of Electrical and Computer Engineering and Electronic Imaging Center, New Jersey Institute of Technology, 323 Martin Luther King Boulevard, University Heights, Newark, New Jersey 07102, United States
| | - Thang Ha Quoc Bui
- Department
of Electrical and Computer Engineering and Electronic Imaging Center, New Jersey Institute of Technology, 323 Martin Luther King Boulevard, University Heights, Newark, New Jersey 07102, United States
| | - Durgamadhab Misra
- Department
of Electrical and Computer Engineering and Electronic Imaging Center, New Jersey Institute of Technology, 323 Martin Luther King Boulevard, University Heights, Newark, New Jersey 07102, United States
| | - Abdallah Khreishah
- Department
of Electrical and Computer Engineering and Electronic Imaging Center, New Jersey Institute of Technology, 323 Martin Luther King Boulevard, University Heights, Newark, New Jersey 07102, United States
| | - James Piao
- Epitaxial
Laboratory Inc., Tiana
Place, Dix Hills, New York 11746, United States
| | - Hoang Duy Nguyen
- Vietnam
Academy of Science and Technology, Institute
of Applied Materials Science, 1 Mac Dinh Chi Street, District 1, Ho Chi
Minh City 70001, Vietnam
| | - Khai Quang Le
- Faculty
of Science and Technology, Hoa Sen University, 8 Nguyen Van Trang Street, District 1, Ho Chi Minh City 70001, Vietnam
| | - Hieu Pham Trung Nguyen
- Department
of Electrical and Computer Engineering and Electronic Imaging Center, New Jersey Institute of Technology, 323 Martin Luther King Boulevard, University Heights, Newark, New Jersey 07102, United States
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14
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Liu Q, Liu B, Yang W, Yang B, Zhang X, Labbé C, Portier X, An V, Jiang X. Alignment control and atomically-scaled heteroepitaxial interface study of GaN nanowires. NANOSCALE 2017; 9:5212-5221. [PMID: 28397937 DOI: 10.1039/c7nr00032d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Well-aligned GaN nanowires are promising candidates for building high-performance optoelectronic nanodevices. In this work, we demonstrate the epitaxial growth of well-aligned GaN nanowires on a [0001]-oriented sapphire substrate in a simple catalyst-assisted chemical vapor deposition process and their alignment control. It is found that the ammonia flux plays a key role in dominating the initial nucleation of GaN nanocrystals and their orientation. Typically, significant improvement of the GaN nanowire alignment can be realized at a low NH3 flow rate. X-ray diffraction and cross-sectional scanning electron microscopy studies further verified the preferential orientation of GaN nanowires along the [0001] direction. The growth mechanism of GaN nanowire arrays is also well studied based on cross-sectional high-resolution transmission electron microscopy (HRTEM) characterization and it is observed that GaN nanowires have good epitaxial growth on the sapphire substrate following the crystallographic relationship between (0001)GaN∥(0001)sapphire and (101[combining macron]0)GaN∥(112[combining macron]0)sapphire. Most importantly, periodic misfit dislocations are also experimentally observed in the interface region due to the large lattice mismatch between the GaN nanowire and the sapphire substrate, and the formation of such dislocations will favor the release of structural strain in GaN nanowires. HRTEM analysis also finds the existence of "type I" stacking faults and voids inside the GaN nanowires. Optical investigation suggests that the GaN nanowire arrays have strong emission in the UV range, suggesting their crystalline nature and chemical purity. The achievement of aligned GaN nanowires will further promote the wide applications of GaN nanostructures toward diverse high-performance optoelectronic nanodevices including nano-LEDs, photovoltaic cells, photodetectors etc.
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Affiliation(s)
- Qingyun Liu
- Shenyang National Laboratory for Materials Science (SYNL), Institute of Metal Research (IMR), Chinese Academy of Sciences (CAS), No. 72, Wenhua Road, Shenhe District, Shenyang 110016, China.
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15
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III-nitride core-shell nanorod array on quartz substrates. Sci Rep 2017; 7:45345. [PMID: 28345641 PMCID: PMC5366955 DOI: 10.1038/srep45345] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 02/27/2017] [Indexed: 12/13/2022] Open
Abstract
We report the fabrication of near-vertically elongated GaN nanorods on quartz substrates. To control the preferred orientation and length of individual GaN nanorods, we combined molecular beam epitaxy (MBE) with pulsed-mode metal-organic chemical vapor deposition (MOCVD). The MBE-grown buffer layer was composed of GaN nanograins exhibiting an ordered surface and preferred orientation along the surface normal direction. Position-controlled growth of the GaN nanorods was achieved by selective-area growth using MOCVD. Simultaneously, the GaN nanorods were elongated by the pulsed-mode growth. The microstructural and optical properties of both GaN nanorods and InGaN/GaN core-shell nanorods were then investigated. The nanorods were highly crystalline and the core-shell structures exhibited optical emission properties, indicating the feasibility of fabricating III-nitride nano-optoelectronic devices on amorphous substrates.
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16
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Yan Z, Jiang L. Modified Continuum Mechanics Modeling on Size-Dependent Properties of Piezoelectric Nanomaterials: A Review. NANOMATERIALS 2017; 7:nano7020027. [PMID: 28336861 PMCID: PMC5333012 DOI: 10.3390/nano7020027] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 01/16/2017] [Accepted: 01/18/2017] [Indexed: 12/03/2022]
Abstract
Piezoelectric nanomaterials (PNs) are attractive for applications including sensing, actuating, energy harvesting, among others in nano-electro-mechanical-systems (NEMS) because of their excellent electromechanical coupling, mechanical and physical properties. However, the properties of PNs do not coincide with their bulk counterparts and depend on the particular size. A large amount of efforts have been devoted to studying the size-dependent properties of PNs by using experimental characterization, atomistic simulation and continuum mechanics modeling with the consideration of the scale features of the nanomaterials. This paper reviews the recent progresses and achievements in the research on the continuum mechanics modeling of the size-dependent mechanical and physical properties of PNs. We start from the fundamentals of the modified continuum mechanics models for PNs, including the theories of surface piezoelectricity, flexoelectricity and non-local piezoelectricity, with the introduction of the modified piezoelectric beam and plate models particularly for nanostructured piezoelectric materials with certain configurations. Then, we give a review on the investigation of the size-dependent properties of PNs by using the modified continuum mechanics models, such as the electromechanical coupling, bending, vibration, buckling, wave propagation and dynamic characteristics. Finally, analytical modeling and analysis of nanoscale actuators and energy harvesters based on piezoelectric nanostructures are presented.
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Affiliation(s)
- Zhi Yan
- Department of Mechanics, Huazhong University of Science and Technology, Wuhan 430074, China.
- Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment, Luoyu Road 1037, Wuhan 430074, China.
| | - Liying Jiang
- Department of Mechanical and Materials Engineering, The University of Western Ontario, London, ON N6A 5B9, Canada.
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17
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Li H, Zhao G, Wei H, Wang L, Chen Z, Yang S. Growth of Well-Aligned InN Nanorods on Amorphous Glass Substrates. NANOSCALE RESEARCH LETTERS 2016; 11:270. [PMID: 27229517 PMCID: PMC4880805 DOI: 10.1186/s11671-016-1482-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 05/13/2016] [Indexed: 06/05/2023]
Abstract
The growth of well-aligned nanorods on amorphous substrates can pave the way to fabricate large-scale and low-cost devices. In this work, we successfully prepared vertically well-aligned c-axis InN nanorods on amorphous glass substrate by metal-organic chemical vapor deposition. The products formed directly on bare glass are randomly oriented without preferential growth direction. By inserting a GaN/Ti interlayer, the nanowire alignment can be greatly improved as indicated by scanning electron microscopy and X-ray diffraction.
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Affiliation(s)
- Huijie Li
- Key Laboratory of Semiconductor Materials Science, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, P. O. Box 912, Beijing, 100083, People's Republic of China.
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
| | - Guijuan Zhao
- Key Laboratory of Semiconductor Materials Science, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, P. O. Box 912, Beijing, 100083, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Hongyuan Wei
- Key Laboratory of Semiconductor Materials Science, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, P. O. Box 912, Beijing, 100083, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Lianshan Wang
- Key Laboratory of Semiconductor Materials Science, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, P. O. Box 912, Beijing, 100083, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Zhen Chen
- LatticePower (Jiangxi) Corporation, No. 699 North Aixihu Road; National High-Tech Industrial Development Zone, Nanchang, 330029, Jiangxi, Peoples Republic of China
| | - Shaoyan Yang
- Key Laboratory of Semiconductor Materials Science, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, P. O. Box 912, Beijing, 100083, People's Republic of China.
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
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18
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Kibria MG, Qiao R, Yang W, Boukahil I, Kong X, Chowdhury FA, Trudeau ML, Ji W, Guo H, Himpsel FJ, Vayssieres L, Mi Z. Atomic-Scale Origin of Long-Term Stability and High Performance of p-GaN Nanowire Arrays for Photocatalytic Overall Pure Water Splitting. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:8388-8397. [PMID: 27456856 DOI: 10.1002/adma.201602274] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 06/20/2016] [Indexed: 06/06/2023]
Abstract
The atomic-scale origin of the unusually high performance and long-term stability of wurtzite p-GaN oriented nanowire arrays is revealed. Nitrogen termination of both the polar (0001¯) top face and the nonpolar (101¯0) side faces of the nanowires is essential for long-term stability and high efficiency. Such a distinct atomic configuration ensures not only stability against (photo) oxidation in air and in water/electrolyte but, as importantly, also provides the necessary overall reverse crystal polarization needed for efficient hole extraction in p-GaN.
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Affiliation(s)
- Md Golam Kibria
- Department of Electrical & Computer Engineering, McGill University, Montreal, QC, H3A0E9, Canada
| | - Ruimin Qiao
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Wanli Yang
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Idris Boukahil
- Department of Physics, University of Wisconsin Madison, Madison, WI, 53706, USA
| | - Xianghua Kong
- Department of Physics, McGill University, Montreal, QC, H3A2T8, Canada
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials and Micro-Nano Devices, Renmin University of China, Beijing, 100872, P. R. China
| | - Faqrul Alam Chowdhury
- Department of Electrical & Computer Engineering, McGill University, Montreal, QC, H3A0E9, Canada
| | - Michel L Trudeau
- Science des Matériaux, IREQ, Hydro-Québec, Varennes, QC, J3×1S1, Canada
| | - Wei Ji
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials and Micro-Nano Devices, Renmin University of China, Beijing, 100872, P. R. China
| | - Hong Guo
- Department of Physics, McGill University, Montreal, QC, H3A2T8, Canada
| | - F J Himpsel
- Department of Physics, University of Wisconsin Madison, Madison, WI, 53706, USA.
| | - Lionel Vayssieres
- International Research Center for Renewable Energy, School of Energy & Power Engineering, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
| | - Zetian Mi
- Department of Electrical & Computer Engineering, McGill University, Montreal, QC, H3A0E9, Canada.
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19
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Sobanska M, Fernández-Garrido S, Zytkiewicz ZR, Tchutchulashvili G, Gieraltowska S, Brandt O, Geelhaar L. Self-assembled growth of GaN nanowires on amorphous Al x O y : from nucleation to the formation of dense nanowire ensembles. NANOTECHNOLOGY 2016; 27:325601. [PMID: 27354451 DOI: 10.1088/0957-4484/27/32/325601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present a comprehensive description of the self-assembled nucleation and growth of GaN nanowires (NWs) by plasma-assisted molecular beam epitaxy on amorphous Al x O y buffers (a-Al x O y ) prepared by atomic layer deposition. The results are compared with those obtained on nitridated Si(111). Using line-of-sight quadrupole mass spectrometry, we analyze in situ the incorporation of Ga starting from the incubation and nucleation stages till the formation of the final nanowire ensemble and observe qualitatively the same time dependence for the two types of substrates. However, on a-Al x O y the incubation time is shorter and the nucleation faster than on nitridated Si. Moreover, on a-Al x O y we observe a novel effect of decrease in incorporated Ga flux for long growth durations which we explain by coalescence of NWs leading to reduction of the GaN surface area where Ga may reside. Dedicated samples are used to analyze the evolution of surface morphology. In particular, no GaN nuclei are detected when growth is interrupted during the incubation stage. Moreover, for a-Al x O y , the same shape transition from spherical cap-shaped GaN crystallites to the NW-like geometry is found as it is known for nitridated Si. However, while the critical radius for this transition is only slightly larger for a-Al x O y than for nitridated Si, the critical height is more than six times larger for a-Al x O y . Finally, we observe that in fully developed NW ensembles, the substrate no longer influences growth kinetics and the same N-limited axial growth rate is measured on both substrates. We conclude that the same nucleation and growth processes take place on a-Al x O y as on nitridated Si and that these processes are of a general nature. Quantitatively, nucleation proceeds somewhat differently, which indicates the influence of the substrate, but once shadowing limits growth processes to the upper part of the NW ensemble, they are not affected anymore by the type of substrate.
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Affiliation(s)
- M Sobanska
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
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20
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Wang Y, Fan S, AlOtaibi B, Wang Y, Li L, Mi Z. A Monolithically Integrated Gallium Nitride Nanowire/Silicon Solar Cell Photocathode for Selective Carbon Dioxide Reduction to Methane. Chemistry 2016; 22:8809-13. [DOI: 10.1002/chem.201601642] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Yichen Wang
- Department of Electrical and Computer Engineering; McGill University; 3480 University Street Montreal QC H3A 0E9 Canada
| | - Shizhao Fan
- Department of Electrical and Computer Engineering; McGill University; 3480 University Street Montreal QC H3A 0E9 Canada
| | - Bandar AlOtaibi
- Department of Electrical and Computer Engineering; McGill University; 3480 University Street Montreal QC H3A 0E9 Canada
| | - Yongjie Wang
- Department of Electrical and Computer Engineering; McGill University; 3480 University Street Montreal QC H3A 0E9 Canada
| | - Lu Li
- Department of Electrical and Computer Engineering; McGill University; 3480 University Street Montreal QC H3A 0E9 Canada
| | - Zetian Mi
- Department of Electrical and Computer Engineering; McGill University; 3480 University Street Montreal QC H3A 0E9 Canada
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21
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Liu B, Yang B, Yuan F, Liu Q, Shi D, Jiang C, Zhang J, Staedler T, Jiang X. Defect-Induced Nucleation and Epitaxy: A New Strategy toward the Rational Synthesis of WZ-GaN/3C-SiC Core-Shell Heterostructures. NANO LETTERS 2015; 15:7837-7846. [PMID: 26517395 DOI: 10.1021/acs.nanolett.5b02454] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this work, we demonstrate a new strategy to create WZ-GaN/3C-SiC heterostructure nanowires, which feature controllable morphologies. The latter is realized by exploiting the stacking faults in 3C-SiC as preferential nucleation sites for the growth of WZ-GaN. Initially, cubic SiC nanowires with an average diameter of ∼100 nm, which display periodic stacking fault sections, are synthesized in a chemical vapor deposition (CVD) process to serve as the core of the heterostructure. Subsequently, hexagonal wurtzite-type GaN shells with different shapes are grown on the surface of 3C-SiC wire core. In this context, it is possible to obtain two types of WZ-GaN/3C-SiC heterostructure nanowires by means of carefully controlling the corresponding CVD reactions. Here, the stacking faults, initially formed in 3C-SiC nanowires, play a key role in guiding the epitaxial growth of WZ-GaN as they represent surface areas of the 3C-SiC nanowires that feature a higher surface energy. A dedicated structural analysis of the interfacial region by means of high-resolution transmission electron microscopy (HRTEM) revealed that the disordering of the atom arrangements in the SiC defect area promotes a lattice-matching with respect to the WZ-GaN phase, which results in a preferential nucleation. All WZ-GaN crystal domains exhibit an epitaxial growth on 3C-SiC featuring a crystallographic relationship of [12̅10](WZ-GaN) //[011̅](3C-SiC), (0001)(WZ-GaN)//(111)(3C-SiC), and d(WZ-GaN(0001)) ≈ 2d(3C-SiC(111)). The approach to utilize structural defects of a nanowire core to induce a preferential nucleation of foreign shells generally opens up a number of opportunities for the epitaxial growth of a wide range of semiconductor nanostructures which are otherwise impossible to acquire. Consequently, this concept possesses tremendous potential for the applications of semiconductor heterostructures in various fields such as optics, electrics, electronics, and photocatalysis for energy harvesting and environment processing.
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Affiliation(s)
| | | | | | | | | | | | | | - Thorsten Staedler
- Institute of Materials Engineering, University of Siegen, Germany , Paul-Bonatz-Strasse 9-11, 57076 Siegen, Germany
| | - Xin Jiang
- Institute of Materials Engineering, University of Siegen, Germany , Paul-Bonatz-Strasse 9-11, 57076 Siegen, Germany
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22
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Sarwar ATMG, Carnevale SD, Yang F, Kent TF, Jamison JJ, McComb DW, Myers RC. Semiconductor Nanowire Light-Emitting Diodes Grown on Metal: A Direction Toward Large-Scale Fabrication of Nanowire Devices. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:5402-5408. [PMID: 26307552 DOI: 10.1002/smll.201501909] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 07/17/2015] [Indexed: 06/04/2023]
Abstract
Bottom-up nanowires are attractive for realizing semiconductor devices with extreme heterostructures because strain relaxation through the nanowire sidewalls allows the combination of highly lattice mismatched materials without creating dislocations. The resulting nanowires are used to fabricate light-emitting diodes (LEDs), lasers, solar cells, and sensors. However, expensive single crystalline substrates are commonly used as substrates for nanowire heterostructures as well as for epitaxial devices, which limits the manufacturability of nanowire devices. Here, nanowire LEDs directly grown and electrically integrated on metal are demonstrated. Optical and structural measurements reveal high-quality, vertically aligned GaN nanowires on molybdenum and titanium films. Transmission electron microscopy confirms the composition variation in the polarization-graded AlGaN nanowire LEDs. Blue to green electroluminescence is observed from InGaN quantum well active regions, while GaN active regions exhibit ultraviolet emission. These results demonstrate a pathway for large-scale fabrication of solid state lighting and optoelectronics on metal foils or sheets.
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Affiliation(s)
- A T M Golam Sarwar
- Department of Electrical and Computer Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Santino D Carnevale
- Department of Electrical and Computer Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Fan Yang
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Thomas F Kent
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - John J Jamison
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - David W McComb
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Roberto C Myers
- Department of Electrical and Computer Engineering, The Ohio State University, Columbus, OH, 43210, USA
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210, USA
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23
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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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24
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Sadaf SM, Ra YH, Nguyen HPT, Djavid M, Mi Z. Alternating-Current InGaN/GaN Tunnel Junction Nanowire White-Light Emitting Diodes. NANO LETTERS 2015; 15:6696-701. [PMID: 26384135 DOI: 10.1021/acs.nanolett.5b02515] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The current LED lighting technology relies on the use of a driver to convert alternating current (AC) to low-voltage direct current (DC) power, a resistive p-GaN contact layer to inject positive charge carriers (holes) for blue light emission, and rare-earth doped phosphors to down-convert blue photons into green/red light, which have been identified as some of the major factors limiting the device efficiency, light quality, and cost. Here, we show that multiple-active region phosphor-free InGaN nanowire white LEDs connected through a polarization engineered tunnel junction can fundamentally address the afore-described challenges. Such a p-GaN contact-free LED offers the benefit of carrier regeneration, leading to enhanced light intensity and reduced efficiency droop. Moreover, through the monolithic integration of p-GaN up and p-GaN down nanowire LED structures on the same substrate, we have demonstrated, for the first time, AC operated LEDs on a Si platform, which can operate efficiently in both polarities (positive and negative) of applied voltage.
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Affiliation(s)
- S M Sadaf
- Department of Electrical and Computer Engineering, McGill University , 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - Y-H Ra
- Department of Electrical and Computer Engineering, McGill University , 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - H P T Nguyen
- Department of Electrical and Computer Engineering, McGill University , 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - M Djavid
- Department of Electrical and Computer Engineering, McGill University , 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - Z Mi
- Department of Electrical and Computer Engineering, McGill University , 3480 University Street, Montreal, Quebec H3A 0E9, Canada
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25
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AlOtaibi B, Fan S, Wang D, Ye J, Mi Z. Wafer-Level Artificial Photosynthesis for CO2 Reduction into CH4 and CO Using GaN Nanowires. ACS Catal 2015. [DOI: 10.1021/acscatal.5b00776] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bandar AlOtaibi
- Department
of Electrical and Computer Engineering, McGill University, 3480
University Street, Montreal, Quebec H3A 0E9, Canada
| | - Shizhao Fan
- Department
of Electrical and Computer Engineering, McGill University, 3480
University Street, Montreal, Quebec H3A 0E9, Canada
| | - Defa Wang
- TU-NIMS
Joint Research Center, School of Materials Science and Engineering, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China
- Collaborative Innovation
Center of Chemical Science and Engineering (Tianjin), 92 Weijin Road, Nankai District, Tianjin 300072, China
| | - Jinhua Ye
- TU-NIMS
Joint Research Center, School of Materials Science and Engineering, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China
- International
Center for Materials Nanoarchitectonics (WPI-MANA) and Environmental
Remediation Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 Japan
| | - Zetian Mi
- Department
of Electrical and Computer Engineering, McGill University, 3480
University Street, Montreal, Quebec H3A 0E9, Canada
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26
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Pu YC, Kibria MG, Mi Z, Zhang JZ. Ultrafast Exciton Dynamics in InGaN/GaN and Rh/Cr2O3 Nanoparticle-Decorated InGaN/GaN Nanowires. J Phys Chem Lett 2015; 6:2649-56. [PMID: 26266748 DOI: 10.1021/acs.jpclett.5b00909] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Ultrafast exciton and charge-carrier dynamics in InGaN/GaN nanowires (NWs) with and without Rh/Cr2O3 nanoparticle (NP) decoration have been investigated using femtosecond transient absorption (TA) techniques with excitation at 415 nm and white-light probe (450-700 nm). By comparing the TA profiles between InGaN/GaN and InGaN/GaN-Rh/Cr2O3 NWs, an additional decay component on the medium time scale (∼50 ps) was identified with Rh/Cr2O3 decoration, which is attributed to interfacial charge transfer from InGaN/GaN NWs to Rh/Cr2O3 NPs, desired for light energy conversion applications. This is consistent with reduced photoluminescence (PL) of the NWs by the Rh/Cr2O3 NPs. A kinetic model was developed to explain the TA results and gain further insight into the exciton and charge-carrier dynamics.
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Affiliation(s)
- Ying-Chih Pu
- †Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, California 95064, United States
| | - M G Kibria
- ‡Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Québec H3A 0E9, Canada
| | - Zetian Mi
- ‡Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Québec H3A 0E9, Canada
| | - Jin Z Zhang
- †Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, California 95064, United States
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27
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Park Y, Jahangir S, Park Y, Bhattacharya P, Heo J. InGaN/GaN nanowires grown on SiO(2) and light emitting diodes with low turn on voltages. OPTICS EXPRESS 2015; 23:A650-A656. [PMID: 26072889 DOI: 10.1364/oe.23.00a650] [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
GaN nanowires and InGaN disk heterostructures are grown on an amorphous SiO2 layer by a plasma-assisted molecular beam epitaxy. Structural studies using scanning electron microscopy and high-resolution transmission electron microscopy reveal that the nanowires grow vertically without any extended defect similarly to nanowires grown on Si. The as-grown nanowires have an intermediate region consisting of Ga, O, and Si rather than SiNx at the interface between the nanowires and SiO2. The measured photoluminescence shows a variation of peak wavelengths ranging from 580 nm to 635 nm because of non-uniform indium incorporation. The nanowires grown on SiO2 are successfully transferred to a flexible polyimide sheet by Au-welding and epitaxial lift-off processes. The light-emitting diodes fabricated with the transferred nanowires are characterized by a turn-on voltage of approximately 4 V. The smaller turn-on voltage in contrast to those of conventional nanowire light-emitting diodes is due to the absence of an intermediate layer, which is removed during an epitaxial lift-off process. The measured electroluminescence shows peak wavelengths of 610-616 nm with linewidths of 116-123 nm.
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Zhao S, Connie AT, Dastjerdi MHT, Kong XH, Wang Q, Djavid M, Sadaf S, Liu XD, Shih I, Guo H, Mi Z. Aluminum nitride nanowire light emitting diodes: Breaking the fundamental bottleneck of deep ultraviolet light sources. Sci Rep 2015; 5:8332. [PMID: 25684335 PMCID: PMC4329565 DOI: 10.1038/srep08332] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 01/05/2015] [Indexed: 12/24/2022] Open
Abstract
Despite broad interest in aluminum gallium nitride (AlGaN) optoelectronic devices for deep ultraviolet (DUV) applications, the performance of conventional Al(Ga)N planar devices drastically decays when approaching the AlN end, including low internal quantum efficiencies (IQEs) and high device operation voltages. Here we show that these challenges can be addressed by utilizing nitrogen (N) polar Al(Ga)N nanowires grown directly on Si substrate. By carefully tuning the synthesis conditions, a record IQE of 80% can be realized with N-polar AlN nanowires, which is nearly ten times higher compared to high quality planar AlN. The first 210 nm emitting AlN nanowire light emitting diodes (LEDs) were achieved, with a turn on voltage of about 6 V, which is significantly lower than the commonly observed 20 – 40 V. This can be ascribed to both efficient Mg doping by controlling the nanowire growth rate and N-polarity induced internal electrical field that favors hole injection. In the end, high performance N-polar AlGaN nanowire LEDs with emission wavelengths covering the UV-B/C bands were also demonstrated.
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Affiliation(s)
- S Zhao
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec, Canada H3A 0E9
| | - A T Connie
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec, Canada H3A 0E9
| | - M H T Dastjerdi
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec, Canada H3A 0E9
| | - X H Kong
- Department of Physics, McGill University, 3600 University Street, Montreal, Quebec, Canada H3A 2T8
| | - Q Wang
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec, Canada H3A 0E9
| | - M Djavid
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec, Canada H3A 0E9
| | - S Sadaf
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec, Canada H3A 0E9
| | - X D Liu
- Facility for Electron Microscopy Research, McGill University, 3640 University Street, Montreal, Quebec H3A 0C7
| | - I Shih
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec, Canada H3A 0E9
| | - H Guo
- Department of Physics, McGill University, 3600 University Street, Montreal, Quebec, Canada H3A 2T8
| | - Z Mi
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec, Canada H3A 0E9
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Wang R, Nguyen HPT, Connie AT, Lee J, Shih I, Mi Z. Color-tunable, phosphor-free InGaN nanowire light-emitting diode arrays monolithically integrated on silicon. OPTICS EXPRESS 2014; 22 Suppl 7:A1768-A1775. [PMID: 25607491 DOI: 10.1364/oe.22.0a1768] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We demonstrate controllable and tunable full color light generation through the monolithic integration of blue, green/yellow, and orange/red InGaN nanowire light-emitting diodes (LEDs). Such multi-color nanowire LED arrays are fabricated directly on Si substrate using a three-step selective area molecular beam epitaxy growth process. The lateral-arranged multi-color subpixels enable controlled light mixing at the chip-level and yield color-tunable light emission with CCT values in the range from 1900 K to 6800 K, while maintaining excellent color rendering capability. This work provides a viable approach for achieving micron and nanoscale tunable full-color LED arrays without the compromise between the device efficiency and light quality associated with conventional phosphor-based LEDs.
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Zhang J, Wang C, Bowen C. Piezoelectric effects and electromechanical theories at the nanoscale. NANOSCALE 2014; 6:13314-13327. [PMID: 25315991 DOI: 10.1039/c4nr03756a] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Considerable effort has been made to study the piezoelectric effect on the nanoscale, which serves as a physical basis for a wide range of smart nanodevices and nanoelectronics. This paper reviews recent progress in the research on the piezoelectric properties and electromechanical effects of piezoelectric nanomaterials (PNs). The review begins with an introduction to existing PNs which exhibit a diverse range of atomic structures and configurations. The nanoscale measurement of their effective piezoelectric coefficients (EPCs) is summarised with an emphasis on the major factors determining the piezoelectric properties of PNs. The paper concludes with a review of the electromechanical theories that are able to capture the small-scale effects on PNs, which include the surface piezoelectricity, flexoelectricity and Eringen's nonlocal theory. In contrast to the classical theories, two types of EPCs are defined, which were found to be size-dependent and loading condition-selective.
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Affiliation(s)
- Jin Zhang
- College of Engineering, Swansea University, Singleton Park, Swansea, Wales SA2 8PP, UK.
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Zhao S, Le BH, Liu DP, Liu XD, Kibria MG, Szkopek T, Guo H, Mi Z. p-Type InN nanowires. NANO LETTERS 2013; 13:5509-5513. [PMID: 24090401 DOI: 10.1021/nl4030819] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this Letter, we demonstrate that with the merit of nanowire structure and a self-catalytic growth process p-type InN can be realized for the first time by "direct" magnesium (Mg) doping. The presence of Mg acceptor energy levels in InN is confirmed by photoluminescence experiments, and a direct evidence of p-type conduction is demonstrated unambiguously by studying the transfer characteristics of InN nanowire field effect transistors. Moreover, the near-surface Fermi-level of InN can be tuned from nearly intrinsic to p-type degenerate by controlling Mg dopant incorporation, which is in contrast to the commonly observed electron accumulation on the grown surfaces of Mg-doped InN films. First-principle calculation using the VASP electronic package further shows that the p-type surface formed on Mg-doped InN nanowires is highly stable energetically.
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Affiliation(s)
- S Zhao
- Department of Electrical and Computer Engineering, McGill University 3480 University Street, Montreal, Quebec H3A 0E9, Canada
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AlOtaibi B, Nguyen HPT, Zhao S, Kibria MG, Fan S, Mi Z. Highly stable photoelectrochemical water splitting and hydrogen generation using a double-band InGaN/GaN core/shell nanowire photoanode. NANO LETTERS 2013; 13:4356-4361. [PMID: 23927558 DOI: 10.1021/nl402156e] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We report on the first demonstration of stable photoelectrochemical water splitting and hydrogen generation on a double-band photoanode in acidic solution (hydrogen bromide), which is achieved by InGaN/GaN core/shell nanowire arrays grown on Si substrate using catalyst-free molecular beam epitaxy. The nanowires are doped n-type using Si to reduce the surface depletion region and increase current conduction. Relatively high incident-photon-to-current-conversion efficiency (up to ~27%) is measured under ultraviolet and visible light irradiation. Under simulated sunlight illumination, steady evolution of molecular hydrogen is further demonstrated.
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Affiliation(s)
- B AlOtaibi
- Department of Electrical and Computer Engineering, McGill University , 3480 University Street, Montreal, Quebec H3A 0E9, Canada
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