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Ahn MJ, Jeong WS, Shim KY, Kang S, Kim H, Kim DS, Jhin J, Kim J, Byun D. Selective-Area Growth Mechanism of GaN Microrods on a Plateau Patterned Substrate. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2462. [PMID: 36984342 PMCID: PMC10053046 DOI: 10.3390/ma16062462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/12/2023] [Accepted: 03/17/2023] [Indexed: 06/18/2023]
Abstract
This study provides experimental evidence regarding the mechanism of gallium nitride (GaN) selective-area growth (SAG) on a polished plateau-patterned sapphire substrate (PP-PSS), on which aluminum nitride (AlN) buffer layers are deposited under the same deposition conditions. The SAG of GaN was only observed on the plateau region of the PP-PSS, irrespective of the number of growth cycles. Indirect samples deposited on the bare c-plane substrate were prepared to determine the difference between the AlN buffer layers in the plateau region and silicon oxide (SiO2). The AlN buffer layer in the plateau region exhibited a higher surface energy, and its crystal orientation is indicated by AlN [001]. In contrast, regions other than the plateau region did not exhibit crystallinity and presented lower surface energies. The direct analysis results of PP-PSS using transmission electron microscopy (TEM) and electron backscattered diffraction (EBSD) are similar to the results of the indirect samples. Therefore, under the same conditions, the GaN SAG of the deposited layer is related to crystallinity, crystal orientation, and surface energy.
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Affiliation(s)
- Min-joo Ahn
- Department of Materials Science and Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Woo-seop Jeong
- Department of Materials Science and Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Kyu-yeon Shim
- Department of Materials Science and Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Seongho Kang
- Department of Materials Science and Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Hwayoung Kim
- Department of Materials Science and Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Dae-sik Kim
- Natural Science Research, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Junggeun Jhin
- Advanced View Technology Inc., Ansan 15588, Republic of Korea
| | - Jaekyun Kim
- Department of Photonics and Nanoelectronics, Hanyang University, Ansan 15588, Republic of Korea
| | - Dongjin Byun
- Department of Materials Science and Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
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Wang R, Cheng S, Vanka S, Botton GA, Mi Z. Selective area grown AlInGaN nanowire arrays with core-shell structures for photovoltaics on silicon. NANOSCALE 2021; 13:8163-8173. [PMID: 33881116 DOI: 10.1039/d1nr00468a] [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
To pave the way for InGaN-on-Si integrated photovoltaics, uniform and close-packed n-GaN/(Al)InGaN/p-GaN nanowire (NW) arrays with a ∼0.29 μm thick absorption segment of ∼2.35 eV energy bandgap were fabricated on a Si substrate using Ti-mask selective area growth (SAG) in a molecular beam epitaxy (MBE) chamber. Instead of using thick and insulting buffer layers, this SAG process was realized by employing a 3 nm AlN/GaN: Ge buffer layer to facilitate electrical and thermal conduction between NWs and Si. Scanning transmission electron microscopy and high-resolution electron energy loss spectroscopy mapping revealed the discontinuities of AlN and the embedments of GaN:Ge which contribute to a negligible resistance of the NWs-on-Si interface. AlInGaN active segment exhibits core-shell structures, which suppress nonradiative surface recombination at NW surfaces. Working of AlInGaN core-shell NW solar cells was demonstrated with improved open-circuit voltage (Voc) and higher energy conversion efficiency (η) than those reported for InGaN NW solar cells. Stable output characteristics including the Voc of 1.41 V and η of 2.46% were obtained under 30-Sun illuminations. Such NWs-on-Si devices use Si substrate as the bottom electrode. With a low series resistance of ∼1 Ω, this work paves the way to monolithically integrate MBE-SAG III-nitride devices and Si-based electronics, such as Si solar cells and CMOS devices.
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Affiliation(s)
- Renjie Wang
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, QC H3A 0E9, Canada.
| | - Shaobo Cheng
- Department of Materials Science and Engineering, Canadian Centre for Electron Microscopy, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4 M1, Canada
| | - Srinivas Vanka
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, QC H3A 0E9, Canada. and Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Avenue, Ann Arbor, Michigan 48109, USA
| | - Gianluigi A Botton
- Department of Materials Science and Engineering, Canadian Centre for Electron Microscopy, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4 M1, Canada
| | - Zetian Mi
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, QC H3A 0E9, Canada. and Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Avenue, Ann Arbor, Michigan 48109, USA
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Gómez VJ, Graczyk M, Jam RJ, Lehmann S, Maximov I. Wafer-scale nanofabrication of sub-100 nm arrays by deep-UV displacement Talbot lithography. NANOTECHNOLOGY 2020; 31:295301. [PMID: 32259808 DOI: 10.1088/1361-6528/ab8764] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In this manuscript, we demonstrate the potential of replacing the standard bottom anti-reflective coating (BARC) with a polymethylglutarimide (PMGI) layer for wafer-scale nanofabrication by means of deep-UV displacement talbot lithography (DTL). PMGI is functioning as a developable non-UV sensitive bottom anti-reflective coating (DBARC). After introducing the fabrication process using a standard BARC-based coating and the novel PMGI-based one, the DTL nanopatterning capabilities for both coatings are compared by means of the fabrication of etched nanoholes in a dielectric layer and metal nanodots made by lift-off. Improvement of DTL capabilities are attributed to a reduction of process complexity by avoiding the use of O2 plasma etching of the BARC layer. We show the capacity of this approach to produce nanoholes or nanodots with diameters ranging from 95 to 200 nm at a wafer-scale using only one mask and a proper exposing dose. The minimum diameter of the nanoholes is reduced from 118 to 95 nm when using the PMGI-based coating instead of the BARC-based one. The possibilities opened by the PMGI-based coating are illustrated by the successful fabrication of an array of nanoholes with sub-100 nm diameter for GaAs nanowire growth on a 2″ GaAs wafer, a 2″ nanoimprint lithography (NIL) master stamp, and an array of Au nanodots made by lift-off on a 4″ silica wafer. Therefore, DTL possess the potential for wafer-scale manufacturing of nano-engineered materials.
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Affiliation(s)
- Víctor J Gómez
- Division of Solid State Physics and NanoLund, Lund University, Box 118, SE - 211 00, Lund, Sweden
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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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Roche E, André Y, Avit G, Bougerol C, Castelluci D, Réveret F, Gil E, Médard F, Leymarie J, Jean T, Dubrovskii VG, Trassoudaine A. Circumventing the miscibility gap in InGaN nanowires emitting from blue to red. NANOTECHNOLOGY 2018; 29:465602. [PMID: 30160245 DOI: 10.1088/1361-6528/aaddc1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Widegap III-nitride alloys have enabled new classes of optoelectronic devices including light emitting diodes, lasers and solar cells, but it is admittedly challenging to extend their operating wavelength to the yellow-red band. This requires an increased In content x in In x Ga1-x N, prevented by the indium segregation within the miscibility gap. Beyond the known advantage of dislocation-free growth on dissimilar substrates, nanowires may help to extend the compositional range of InGaN. However, the necessary control over the material homogeneity is still lacking. Here, we present In x Ga1-x N nanowires grown by hydride vapor phase epitaxy on silicon substrates, showing rather homogeneous compositions and emitting from blue to red. The InN fraction in nanowires is tuned from x = 0.17 up to x = 0.7 by changing the growth temperature between 630 °C and 680 °C and adjusting some additional parameters. A dedicated model is presented, which attributes the wide compositional range of nanowires to the purely kinetic growth regime of self-catalyzed InGaN nanowires without macroscopic nucleation. These results may pave a new way for the controlled synthesis of indium-rich InGaN structures for optoelectronic applications in the extended spectral range.
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Affiliation(s)
- Elissa Roche
- Université Clermont Auvergne, CNRS, SIGMA Clermont, Institut Pascal, F-63000 Clermont-Ferrand, France
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Selective Area Growth and Structural Characterization of GaN Nanostructures on Si(111) Substrates. CRYSTALS 2018. [DOI: 10.3390/cryst8090366] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Selective area growth (SAG) of GaN nanowires and nanowalls on Si(111) substrates with AlN and GaN buffer layers grown by plasma-assisted molecular beam epitaxy was studied. For N-polar samples filling of SAG features increased with decreasing lattice mismatch between the SAG and buffer. Defects related to Al–Si eutectic formation were observed in all samples, irrespective of lattice mismatch and buffer layer polarity. Eutectic related defects in the Si surface caused voids in N-polar samples, but not in metal-polar samples. Likewise, inversion domains were present in N-polar, but not metal-polar samples. The morphology of Ga-polar GaN SAG on nitride buffered Si(111) was similar to that of homoepitaxial GaN SAG.
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Characterization of Sub-Monolayer Contaminants at the Regrowth Interface in GaN Nanowires Grown by Selective-Area Molecular Beam Epitaxy. CRYSTALS 2018. [DOI: 10.3390/cryst8040178] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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8
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9
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Puybaret R, Rogers DJ, Gmili YE, Sundaram S, Jordan MB, Li X, Patriarche G, Teherani FH, Sandana EV, Bove P, Voss PL, McClintock R, Razeghi M, Ferguson I, Salvestrini JP, Ougazzaden A. Nanoselective area growth of defect-free thick indium-rich InGaN nanostructures on sacrificial ZnO templates. NANOTECHNOLOGY 2017; 28:195304. [PMID: 28358724 DOI: 10.1088/1361-6528/aa6a43] [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
Nanoselective area growth (NSAG) by metal organic vapor phase epitaxy of high-quality InGaN nanopyramids on GaN-coated ZnO/c-sapphire is reported. Nanopyramids grown on epitaxial low-temperature GaN-on-ZnO are uniform and appear to be single crystalline, as well as free of dislocations and V-pits. They are also indium-rich (with homogeneous 22% indium incorporation) and relatively thick (100 nm). These properties make them comparable to nanostructures grown on GaN and AlN/Si templates, in terms of crystallinity, quality, morphology, chemical composition and thickness. Moreover, the ability to selectively etch away the ZnO allows for the potential lift-off and transfer of the InGaN/GaN nanopyramids onto alternative substrates, e.g. cheaper and/or flexible. This technology offers an attractive alternative to NSAG on AlN/Si as a platform for the fabrication of high quality, thick and indium-rich InGaN monocrystals suitable for cheap, flexible and tunable light-emitting diodes.
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Affiliation(s)
- Renaud Puybaret
- Georgia Institute of Technology, School of Electrical and Computer Engineering, Atlanta, GA 30332, United States of America. CNRS, GT UMI 2958, Georgia Tech Lorraine, 2 Rue Marconi, F-57070 Metz, France
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Ra YH, Wang R, Woo SY, Djavid M, Sadaf SM, Lee J, Botton GA, Mi Z. Full-Color Single Nanowire Pixels for Projection Displays. NANO LETTERS 2016; 16:4608-15. [PMID: 27332859 DOI: 10.1021/acs.nanolett.6b01929] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Multicolor single InGaN/GaN dot-in-nanowire light emitting diodes (LEDs) were fabricated on the same substrate using selective area epitaxy. It is observed that the structural and optical properties of InGaN/GaN quantum dots depend critically on nanowire diameters. Photoluminescence emission of single InGaN/GaN dot-in-nanowire structures exhibits a consistent blueshift with increasing nanowire diameter. This is explained by the significantly enhanced indium (In) incorporation for nanowires with small diameters, due to the more dominant contribution for In incorporation from the lateral diffusion of In adatoms. Single InGaN/GaN nanowire LEDs with emission wavelengths across nearly the entire visible spectral were demonstrated on a single chip by varying the nanowire diameters. Such nanowire LEDs also exhibit superior electrical performance, with a turn-on voltage ∼2 V and negligible leakage current under reverse bias. The monolithic integration of full-color LEDs on a single chip, coupled with the capacity to tune light emission characteristics at the single nanowire level, provides an unprecedented approach to realize ultrasmall and efficient projection display, smart lighting, and on-chip spectrometer.
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Affiliation(s)
- Yong-Ho Ra
- Department of Electrical and Computer Engineering, McGill University , 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - Renjie Wang
- Department of Electrical and Computer Engineering, McGill University , 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - Steffi Y Woo
- Department of Materials Science and Engineering, Canadian Centre for Electron Microscopy, McMaster University , 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
| | - Mehrdad Djavid
- Department of Electrical and Computer Engineering, McGill University , 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - Sharif Md Sadaf
- Department of Electrical and Computer Engineering, McGill University , 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - Jaesoong Lee
- Nano Electronics Lab, Samsung Advanced Institute of Technology , Suwon-si, Gyeonggi-do 443-803, Korea
| | - Gianluigi A Botton
- Department of Materials Science and Engineering, Canadian Centre for Electron Microscopy, McMaster University , 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
| | - Zetian Mi
- Department of Electrical and Computer Engineering, McGill University , 3480 University Street, Montreal, Quebec H3A 0E9, Canada
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11
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Lähnemann J, Corfdir P, Feix F, Kamimura J, Flissikowski T, Grahn HT, Geelhaar L, Brandt O. Radial Stark Effect in (In,Ga)N Nanowires. NANO LETTERS 2016; 16:917-25. [PMID: 26789515 DOI: 10.1021/acs.nanolett.5b03748] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We study the luminescence of unintentionally doped and Si-doped InxGa1-xN nanowires with a low In content (x < 0.2) grown by molecular beam epitaxy on Si substrates. The emission band observed at 300 K from the unintentionally doped samples is centered at much lower energies (800 meV) than expected from the In content measured by X-ray diffractometry and energy dispersive X-ray spectroscopy. This discrepancy arises from the pinning of the Fermi level at the sidewalls of the nanowires, which gives rise to strong radial built-in electric fields. The combination of the built-in electric fields with the compositional fluctuations inherent to (In,Ga)N alloys induces a competition between spatially direct and indirect recombination channels. At elevated temperatures, electrons at the core of the nanowire recombine with holes close to the surface, and the emission from unintentionally doped nanowires exhibits a Stark shift of several hundreds of meV. The competition between spatially direct and indirect transitions is analyzed as a function of temperature for samples with various Si concentrations. We propose that the radial Stark effect is responsible for the broadband absorption of (In,Ga)N nanowires across the entire visible range, which makes these nanostructures a promising platform for solar energy applications.
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Affiliation(s)
- Jonas Lähnemann
- Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Pierre Corfdir
- Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Felix Feix
- Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Jumpei Kamimura
- Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Timur Flissikowski
- Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Holger T Grahn
- Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Lutz Geelhaar
- Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Oliver Brandt
- Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany
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Kishino K, Ishizawa S. Selective-area growth of GaN nanocolumns on Si(111) substrates for application to nanocolumn emitters with systematic analysis of dislocation filtering effect of nanocolumns. NANOTECHNOLOGY 2015; 26:225602. [PMID: 25965011 DOI: 10.1088/0957-4484/26/22/225602] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The growth of highly uniform arrays of GaN nanocolumns with diameters from 122 to 430 nm on Si (111) substrates was demonstrated. The employment of GaN film templates with flat surfaces (root mean square surface roughness of 0.84 nm), which were obtained using an AlN/GaN superlattice (SL) buffer on Si, contributed to the high-quality selective-area growth of nanocolumns using a thin Ti mask of 5 nm thickness by rf-plasma-assisted molecular beam epitaxy. Although the GaN template included a large number of dislocations (dislocation density ∼10(11) cm(-2)), the dislocation filtering effect of nanocolumns was enhanced with decreasing nanocolumn diameters (D). Systematic transmission electron microscopy (TEM) observation enabled us to explain the dependence of the dislocation propagation behavior in nanocolumns on the nanocolumn diameter for the first time. Plan-view TEM analysis was performed for nanocolumns with D = 120-324 nm by slicing the nanocolumns horizontally at a height of ∼300 nm above their bottoms and dislocation propagation through the nanocolumns was analyzed by the cross-sectional TEM observation of nanocolumns with D ∼ 200 nm. It was clarified that dislocations were effectively filtered in the bottom 300 nm region of the nanocolumns, the dislocation density of the nanocolumns decreased with decreasing D, and for narrow nanocolumns with D < 200 nm, dislocation-free crystals were obtained in the upper part of the nanocolumns. The dramatic improvement in the emission properties of GaN nanocolumns observed with decreasing diameter is discussed in relation to the decreased dislocation density. The laser action of InGaN/GaN-based nanocolumn arrays with a nanocolumn diameter of 170 nm and a period of 200 nm on Si under optical excitation was obtained with an emission wavelength of 407 nm. We also fabricated red-emitting InGaN-based nanocolumn light-emitting diodes on Si that operated at a wavelength of 652 nm, demonstrating vertical conduction through the AlN/GaN SL buffer to the Si substrate.
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Affiliation(s)
- Katsumi Kishino
- Department of Engineering and Applied Science, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan. Sophia Nanotechnology Research Center, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan
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13
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Musolino M, Tahraoui A, Fernández-Garrido S, Brandt O, Trampert A, Geelhaar L, Riechert H. Compatibility of the selective area growth of GaN nanowires on AlN-buffered Si substrates with the operation of light emitting diodes. NANOTECHNOLOGY 2015; 26:085605. [PMID: 25656795 DOI: 10.1088/0957-4484/26/8/085605] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
AlN layers with thicknesses between 2 and 14 nm were grown on Si(111) substrates by molecular beam epitaxy. The effect of the AlN layer thickness on the morphology and nucleation time of spontaneously formed GaN nanowires (NWs) was investigated by scanning electron microscopy and line-of-sight quadrupole mass spectrometry, respectively. We observed that the alignment of the NWs grown on these layers improves with increasing layer thickness while their nucleation time decreases. Our results show that 4 nm is the smallest thickness of the AlN layer that allows the growth of well-aligned NWs with short nucleation time. Such an AlN buffer layer was successfully employed, together with a patterned SiOx mask, for the selective-area growth (SAG) of vertical GaN NWs. In addition, we fabricated light-emitting diodes (LEDs) from NW ensembles that were grown by means of self-organization phenomena on bare and on AlN-buffered Si substrates. A careful characterization of the optoelectronic properties of the two devices showed that the performance of NW-LEDs on bare and AlN-buffered Si is similar. Electrical conduction across the AlN buffer is facilitated by a high number of grain boundaries that were revealed by transmission electron microscopy. These results demonstrate that grainy AlN buffer layers on Si are compatible both with the SAG of GaN NWs and LED operation. Therefore, this study is a first step towards the fabrication of LEDs on Si substrates based on homogeneous NW ensembles.
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Affiliation(s)
- M Musolino
- Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, D-10117 Berlin, Germany
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14
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Nguyen HPT, Djavid M, Woo SY, Liu X, Connie AT, Sadaf S, Wang Q, Botton GA, Shih I, Mi Z. Engineering the carrier dynamics of InGaN nanowire white light-emitting diodes by distributed p-AlGaN electron blocking layers. Sci Rep 2015; 5:7744. [PMID: 25592057 PMCID: PMC4296300 DOI: 10.1038/srep07744] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 11/28/2014] [Indexed: 11/30/2022] Open
Abstract
We report on the demonstration of a new type of axial nanowire LED heterostructures, with the use of self-organized InGaN/AlGaN dot-in-a-wire core-shell nanowire arrays. The large bandgap AlGaN shell is spontaneously formed on the sidewall of the nanowire during the growth of AlGaN barrier of the quantum dot active region. As such, nonradiative surface recombination, that dominates the carrier dynamics of conventional axial nanowire LED structures, can be largely eliminated, leading to significantly increased carrier lifetime from ~0.3 ns to 4.5 ns. The luminescence emission is also enhanced by orders of magnitude. Moreover, the p-doped AlGaN barrier layers can function as distributed electron blocking layers (EBLs), which is found to be more effective in reducing electron overflow, compared to the conventional AlGaN EBL. The device displays strong white-light emission, with a color rendering index of ~95. An output power of >5 mW is measured for a 1 mm × 1 mm device, which is more than 500 times stronger than the conventional InGaN axial nanowire LEDs without AlGaN distributed EBLs.
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Affiliation(s)
- Hieu Pham Trung Nguyen
- 1] Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec H3A 0E9, Canada [2] Department of Electrical and Computer Engineering, New Jersey Institute of Technology, University Heights, Newark, New Jersey 07102
| | - Mehrdad Djavid
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - Steffi Y Woo
- Department of Materials Science and Engineering, Canadian Centre for Electron Microscopy and Brockhouse Institute for Materials Research, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 Canada
| | - Xianhe Liu
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - Ashfiqua T Connie
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - Sharif Sadaf
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - Qi Wang
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - Gianluigi A Botton
- Department of Materials Science and Engineering, Canadian Centre for Electron Microscopy and Brockhouse Institute for Materials Research, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 Canada
| | - Ishiang Shih
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - Zetian Mi
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec H3A 0E9, Canada
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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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Bengoechea-Encabo A, Albert S, Lopez-Romero D, Lefebvre P, Barbagini F, Torres-Pardo A, Gonzalez-Calbet JM, Sanchez-Garcia MA, Calleja E. Light-emitting-diodes based on ordered InGaN nanocolumns emitting in the blue, green and yellow spectral range. NANOTECHNOLOGY 2014; 25:435203. [PMID: 25297338 DOI: 10.1088/0957-4484/25/43/435203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The growth of ordered arrays of InGaN/GaN nanocolumnar light emitting diodes by molecular beam epitaxy, emitting in the blue (441 nm), green (502 nm), and yellow (568 nm) spectral range is reported. The device active region, consisting of a nanocolumnar InGaN section of nominally constant composition and 250 to 500 nm length, is free of extended defects, which is in strong contrast to InGaN (planar) layers of similar composition and thickness. Electroluminescence spectra show a very small blue shift with increasing current (almost negligible in the yellow device) and line widths slightly broader than those of state-of-the-art InGaN quantum wells.
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