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Loeto K, Kusch G, Ghosh S, Kappers MJ, Oliver RA. Quantitative analysis of carbon impurity concentrations in GaN epilayers by cathodoluminescence. Micron 2023; 172:103489. [PMID: 37385074 DOI: 10.1016/j.micron.2023.103489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 05/30/2023] [Accepted: 05/30/2023] [Indexed: 07/01/2023]
Abstract
In this work, a technique for quantifying carbon doping concentrations in GaN:C/AlGaN buffer structures using cathodoluminescence (CL) is presented. The method stems from the knowledge that the blue and yellow luminescence intensity in CL spectra of GaN varies with the carbon doping concentration. By calculating the blue and yellow luminescence peak intensities normalised to the peak GaN near-band-edge intensity for GaN layers of known carbon concentrations, calibration curves that show the change in normalised blue and yellow luminescence intensity with carbon concentration in the 1016 - 1019 cm-3 range were derived at both room temperature and 10 K. The utility of such calibration curves was then examined by testing against an unknown sample containing multiple carbon-doped GaN layers. The results obtained from CL using the normalised blue luminescence calibration curves are in close agreement with those from secondary-ion mass spectroscopy (SIMS). However,the method fails when applying calibration curves obtained from the normalised yellow luminescence likely due to the influence of native VGa defects acting in this luminescence region. Although this work shows that indeed CL can be used as a quantitative tool to measure carbon doping concentrations in GaN:C, it is noted that the intrinsic broadening effects innate to CL can make it difficult to differentiate between the intensity variations in thin ( < 500 nm) multilayered GaN:C structures such as the ones studied in this work.
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Affiliation(s)
- K Loeto
- Department of Materials Science and Metallurgy, University of Cambridge, CB3 0FS Cambridge, United Kingdom.
| | - G Kusch
- Department of Materials Science and Metallurgy, University of Cambridge, CB3 0FS Cambridge, United Kingdom
| | - S Ghosh
- Department of Materials Science and Metallurgy, University of Cambridge, CB3 0FS Cambridge, United Kingdom
| | - M J Kappers
- Department of Materials Science and Metallurgy, University of Cambridge, CB3 0FS Cambridge, United Kingdom
| | - R A Oliver
- Department of Materials Science and Metallurgy, University of Cambridge, CB3 0FS Cambridge, United Kingdom
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Sarwar T, Yaras C, Li X, Qu Q, Ku PC. Miniaturizing a Chip-Scale Spectrometer Using Local Strain Engineering and Total-Variation Regularized Reconstruction. Nano Lett 2022; 22:8174-8180. [PMID: 36223431 DOI: 10.1021/acs.nanolett.2c02654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
A wafer-thin chip-scale portable spectrometer suitable for wearable applications based on a reconstructive algorithm was demonstrated. A total of 16 spectral encoders that simultaneously functioned as photodetectors were monolithically integrated on a chip area of 0.16 mm2 by applying local strain engineering in compressively strained InGaN/GaN multiple quantum well heterostructures. The built-in GaN pn junction enabled a direct photocurrent measurement. A non-negative least-squares (NNLS) algorithm with total-variation regularization and a choice of a proper kernel function was shown to deliver a decent spectral reconstruction performance in the wavelength range of 400-645 nm. The accuracies of spectral peak positions and intensity ratios between peaks were found to be 0.97% and 10.4%, respectively. No external optics, such as collimation optics and apertures, were used, enabled by angle-insensitive light-harvesting structures, including an array of cone-shaped backreflectors fabricated on the underside of the sapphire substrate.
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Affiliation(s)
- Tuba Sarwar
- Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Avenue, Ann Arbor, Michigan48109-2122, United States
| | - Can Yaras
- Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Avenue, Ann Arbor, Michigan48109-2122, United States
| | - Xiang Li
- Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Avenue, Ann Arbor, Michigan48109-2122, United States
| | - Qing Qu
- Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Avenue, Ann Arbor, Michigan48109-2122, United States
| | - Pei-Cheng Ku
- Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Avenue, Ann Arbor, Michigan48109-2122, United States
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Pu T, Younis U, Chiu HC, Xu K, Kuo HC, Liu X. Review of Recent Progress on Vertical GaN-Based PN Diodes. Nanoscale Res Lett 2021; 16:101. [PMID: 34097144 PMCID: PMC8184903 DOI: 10.1186/s11671-021-03554-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 05/20/2021] [Indexed: 06/12/2023]
Abstract
As a representative wide bandgap semiconductor material, gallium nitride (GaN) has attracted increasing attention because of its superior material properties (e.g., high electron mobility, high electron saturation velocity, and critical electric field). Vertical GaN devices have been investigated, are regarded as one of the most promising candidates for power electronics application, and are characterized by the capacity for high voltage, high current, and high breakdown voltage. Among those devices, vertical GaN-based PN junction diode (PND) has been considerably investigated and shows great performance progress on the basis of high epitaxy quality and device structure design. However, its device epitaxy quality requires further improvement. In terms of device electric performance, the electrical field crowding effect at the device edge is an urgent issue, which results in premature breakdown and limits the releasing superiorities of the GaN material, but is currently alleviated by edge termination. This review emphasizes the advances in material epitaxial growth and edge terminal techniques, followed by the exploration of the current GaN developments and potential advantages over silicon carbon (SiC) for materials and devices, the differences between GaN Schottky barrier diodes (SBDs) and PNDs as regards mechanisms and features, and the advantages of vertical devices over their lateral counterparts. Then, the review provides an outlook and reveals the design trend of vertical GaN PND utilized for a power system, including with an inchoate vertical GaN PND.
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Affiliation(s)
- Taofei Pu
- College of Materials Science and Engineering, Shenzhen University-Hanshan Normal University Postdoctoral Workstation, Shenzhen University, Shenzhen, 518060, China
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Usman Younis
- College of Materials Science and Engineering, Shenzhen University-Hanshan Normal University Postdoctoral Workstation, Shenzhen University, Shenzhen, 518060, China
| | - Hsien-Chin Chiu
- Department of Electronic Engineering, Chang Gung University, Taoyuan, 333, Taiwan
| | - Ke Xu
- Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China
| | - Hao-Chung Kuo
- Photonic and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu, 300, Taiwan
| | - Xinke Liu
- College of Materials Science and Engineering, Shenzhen University-Hanshan Normal University Postdoctoral Workstation, Shenzhen University, Shenzhen, 518060, China.
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Hawkes PW. Never retire: An introduction to the Baumeister- Humphreys-Spence--Urban birthday issue. Ultramicroscopy 2021;:113323. [PMID: 34301427 DOI: 10.1016/j.ultramic.2021.113323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 05/18/2021] [Indexed: 11/21/2022]
Abstract
The professional and private lives of Wolfgang Baumeister, Sir Colin Humphreys, John C.H. Spence and Knut Urban are retraced on the occasion of their 80th (Humphreys, Urban) and 75th (Baumeister, Spence) birthdays.
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O'Hanlon TJ, Massabuau FCP, Bao A, Kappers MJ, Oliver RA. Directly correlated microscopy of trench defects in InGaN quantum wells. Ultramicroscopy 2021; 231:113255. [PMID: 33762123 DOI: 10.1016/j.ultramic.2021.113255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 02/09/2021] [Accepted: 02/20/2021] [Indexed: 11/30/2022]
Abstract
Directly correlated measurements of the surface morphology, light emission and subsurface structure and composition were carried out on the exact same nanoscale trench defects in InGaN quantum well (QW) structures. Multiple scanning probe, scanning electron and transmission electron microscopy techniques were used to explain the origin of their unusual emission behaviour and the relationship between surface morphology and cathodoluminescence (CL) redshift. Trench defects comprise of an open trench partially or fully enclosing material in InGaN QWs with different CL emission properties to their surroundings. The CL redshift was shown to typically vary with the width of the trench and the prominence of the material enclosed by the trench above its surroundings. Three defects, encompassing typical and atypical features, were prepared into lamellae for transmission electron microscopy (TEM). A cross marker technique was used in the focused ion beam-scanning electron microscope (FIB-SEM) to centre the previously characterised defects in each lamella for further analysis. The defects with wider trenches and strong redshifts in CL emission had their initiating basal-plane stacking fault (BSF) towards the bottom of the QW stack, while the BSF formed near the top of the QW stack for a defect with a narrow trench and minimal redshift. The raised-centre, prominent defect showed a slight increase in QW thickness moving up the QW stack while QW widths in the level-centred defect remained broadly constant. The indium content of the enclosed QWs increased above the BSF positions up to a maximum, with an increase of approximately 4% relative to the surroundings seen for one defect examined. Gross fluctuations in QW width (GWWFs) were present in the surrounding material in this sample but were not seen in QWs enclosed by the defect volumes. These GWWFs have been linked with indium loss from surface step edges two or more monolayers high, and many surface step edges appear pinned by the open trenches, suggesting another reason for the higher indium content seen in QWs enclosed by trench defects.
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Affiliation(s)
- T J O'Hanlon
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK
| | - F C-P Massabuau
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK.
| | - A Bao
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK
| | - M J Kappers
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK
| | - R A Oliver
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK
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Gasmi FZ, Chemam R, Graine R, Boubir B, Meradji H. Structural, electronic, and optical properties of the gallium nitride semiconductor by means of the FP-LAPW method. J Mol Model 2020; 26:356. [PMID: 33245412 DOI: 10.1007/s00894-020-04614-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 11/16/2020] [Indexed: 11/24/2022]
Abstract
In the present paper, the structural, electronic, and linear optical properties of different phases of the gallium nitride (GaN) have been investigated. The zinc blende and wurtzite phases of the GaN have been studied using the full-potential linearized augmented plane wave method (FP-LAPW). In our study, many approximations have been used, such as the local density approximation (LDA), the generalized gradient approximation (GGA), the Engel and Vosko generalized gradient approximation (EV-GGA), and the modified Becke-Johnson (mBJ) potential exchange. As a result, we found a very good agreement with literature experimental results for the energy band gap using the mBJ approximation with a scaling factor of 98% and 80% for the zinc blende and wurtzite phases, respectively.
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Affiliation(s)
- F Z Gasmi
- Radiation Physics Laboratory, Department of Physics, Faculty of Sciences, Badji Mokhtar University, Sidi Amar, Annaba, Algeria.,Research Center in Industrial Technologies, CRTI, Cheraga, P.O. Box 64, 16014, Algiers, Algeria
| | - R Chemam
- Radiation Physics Laboratory, Department of Physics, Faculty of Sciences, Badji Mokhtar University, Sidi Amar, Annaba, Algeria
| | - R Graine
- Radiation Physics Laboratory, Department of Physics, Faculty of Sciences, Badji Mokhtar University, Sidi Amar, Annaba, Algeria. .,Research Center in Industrial Technologies, CRTI, Cheraga, P.O. Box 64, 16014, Algiers, Algeria.
| | - B Boubir
- Research Center in Industrial Technologies, CRTI, Cheraga, P.O. Box 64, 16014, Algiers, Algeria
| | - H Meradji
- Radiation Physics Laboratory, Department of Physics, Faculty of Sciences, Badji Mokhtar University, Sidi Amar, Annaba, Algeria
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Griffiths AD, Herrnsdorf J, McKendry JJD, Strain MJ, Dawson MD. Gallium nitride micro-light-emitting diode structured light sources for multi-modal optical wireless communications systems. Philos Trans A Math Phys Eng Sci 2020; 378:20190185. [PMID: 32114910 PMCID: PMC7062000 DOI: 10.1098/rsta.2019.0185] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Gallium nitride-based light-emitting diodes (LEDs) have revolutionized the lighting industry with their efficient generation of blue and green light. While broad-area (square millimetre) devices have become the dominant LED lighting technology, fabricating LEDs into micro-scale pixels (micro-LEDs) yields further advantages for optical wireless communications (OWC), and for the development of smart-lighting applications such as tracking and imaging. The smaller active areas of micro-LEDs result in high current density operation, providing high modulation bandwidths and increased optical power density. Fabricating micro-LEDs in array formats allows device layouts to be tailored for target applications and provides additional degrees of freedom for OWC systems. Temporal and spatial control is crucial to use the full potential of these micro-scale sources, and is achieved by bonding arrays to pitch-matched complementary metal-oxide-semiconductor control electronics. These compact, integrated chips operate as digital-to-light converters, providing optical signals from digital inputs. Applying the devices as projection systems allows structured light patterns to be used for tracking and self-location, while simultaneously providing space-division multiple access communication links. The high-speed nature of micro-LED array devices, combined with spatial and temporal control, allows many modes of operation for OWC providing complex functionality with chip-scale devices. This article is part of the theme issue 'Optical wireless communication'.
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Braniste T, Cobzac V, Ababii P, Plesco I, Raevschi S, Didencu A, Maniuc M, Nacu V, Ababii I, Tiginyanu I. Mesenchymal stem cells proliferation and remote manipulation upon exposure to magnetic semiconductor nanoparticles. ACTA ACUST UNITED AC 2020; 25:e00435. [PMID: 32090026 PMCID: PMC7025179 DOI: 10.1016/j.btre.2020.e00435] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 11/28/2019] [Accepted: 02/10/2020] [Indexed: 12/11/2022]
Abstract
In this paper, we report on spatial redistribution of bone marrow mesenchymal stem cells loaded with magnetic nanoparticles under the influence of continuously applied magnetic field. Semiconductor nanoparticles were synthesized by epitaxial growth of a GaN thin layer on magnetic sacrificial core consisting of ZnFe2O4 nanoparticles. Different quantities of nanoparticles were incubated in vitro with mesenchymal stem cells. High density of nanoparticles (50 μg/ml) leads to a decrease in the number of cells during incubation, while the density of nanoparticles as low as 10 μg/ml is enough to drag cells in culture and rearrange them according to the spatial distribution of the magnetic field intensity.
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Affiliation(s)
- Tudor Braniste
- National Center for Materials Study and Testing. Technical University of Moldova, Stefan cel Mare av. 168, Chisinau, 2004, Republic of Moldova
- Corresponding authors at: National Center for Materials Study and Testing. Technical University of Moldova, Stefan cel Mare av. 168, Chisinau, 2004, Republic of Moldova.
| | - Vitalie Cobzac
- Laboratory of Tissue Engineering and Cells Cultures. State University of Medicine and Pharmacy “Nicolae Testemiteanu”, Stefan cel Mare av. 165, Chisinau, 2004, Republic of Moldova
| | - Polina Ababii
- Department of Otorhinolaryngology. State University of Medicine and Pharmacy “Nicolae Testemiteanu”, Stefan cel Mare av. 165, Chisinau, 2004, Republic of Moldova
| | - Irina Plesco
- National Center for Materials Study and Testing. Technical University of Moldova, Stefan cel Mare av. 168, Chisinau, 2004, Republic of Moldova
| | - Simion Raevschi
- Department of Physics and Engineering, State University of Moldova, Alexei Mateevici str. 60, Chisinau, 2009, Republic of Moldova
| | - Alexandru Didencu
- Department of Otorhinolaryngology. State University of Medicine and Pharmacy “Nicolae Testemiteanu”, Stefan cel Mare av. 165, Chisinau, 2004, Republic of Moldova
| | - Mihail Maniuc
- Department of Otorhinolaryngology. State University of Medicine and Pharmacy “Nicolae Testemiteanu”, Stefan cel Mare av. 165, Chisinau, 2004, Republic of Moldova
| | - Viorel Nacu
- Laboratory of Tissue Engineering and Cells Cultures. State University of Medicine and Pharmacy “Nicolae Testemiteanu”, Stefan cel Mare av. 165, Chisinau, 2004, Republic of Moldova
| | - Ion Ababii
- Department of Otorhinolaryngology. State University of Medicine and Pharmacy “Nicolae Testemiteanu”, Stefan cel Mare av. 165, Chisinau, 2004, Republic of Moldova
| | - Ion Tiginyanu
- National Center for Materials Study and Testing. Technical University of Moldova, Stefan cel Mare av. 168, Chisinau, 2004, Republic of Moldova
- Academy of Sciences of Moldova, Stefan cel Mare av. 1, Chisinau, 2001, Republic of Moldova
- Corresponding authors at: National Center for Materials Study and Testing. Technical University of Moldova, Stefan cel Mare av. 168, Chisinau, 2004, Republic of Moldova.
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Hirosawa K, Furuta N. Atomization and Changes in Chemical Composition by Laser Ablation in Liquid prior to Determination of Trace Elements in Gallium Nitride. ANAL SCI 2019; 35:557-563. [PMID: 30662017 DOI: 10.2116/analsci.18p542] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Trace elements contained in single-crystal gallium nitride (GaN), which is a refractory material, were determined by inductively coupled plasma mass spectrometry with laser ablation in liquid (LAL) sampling. Particle size analysis by dynamic light scattering confirmed that LAL atomized the single-crystal GaN, and scanning electron microscopy/energy-dispersive X-ray spectrometry revealed that LAL sampling converted the GaN to gallium oxide particles. The atomization and changes in the chemical composition allowed for easy digestion of the sampled particles with nitric acid and a hot plate instead of with hydrochloric or sulfuric acid, a microwave digestion system, and a high-pressure vessel. Trace element analysis revealed the presence of trace Mg, Ge, Y, and Cd in single-crystal GaN, and the detection limits for these elements were 0.1 - 2 mg kg-1. The uncertainty derived from the small amount of sample used, which is a disadvantage of LAL sampling, was reduced by calculating the amount of sample ablated by measuring the concentration of the major element, Ga. We expect that the trace-element profiles of other refractory materials will be able to be determined by using this analytical approach.
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Affiliation(s)
- Koki Hirosawa
- Faculty of Science and Engineering, Department of Applied Chemistry, Chuo University
| | - Naoki Furuta
- Faculty of Science and Engineering, Department of Applied Chemistry, Chuo University
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Prabaswara A, Min JW, Subedi RC, Tangi M, Holguin-Lerma JA, Zhao C, Priante D, Ng TK, Ooi BS. Direct Growth of Single Crystalline GaN Nanowires on Indium Tin Oxide-Coated Silica. Nanoscale Res Lett 2019; 14:45. [PMID: 30721361 PMCID: PMC6363810 DOI: 10.1186/s11671-019-2870-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Accepted: 01/15/2019] [Indexed: 06/09/2023]
Abstract
In this work, we demonstrated the direct growth of GaN nanowires on indium tin oxide (ITO)-coated fused silica substrate. The nanowires were grown catalyst-free using plasma-assisted molecular beam epitaxy (PA-MBE). The effect of growth condition on the morphology and quality of the nanowires is systematically investigated. Structural characterization indicates that the nanowires grow in the (0001) direction directly on top of the ITO layer perpendicular to the substrate plane. Optical characterization of the nanowires shows that yellow luminescence is absent from the nanowire's photoluminescence response, attributed to the low number of defects. Conductive atomic force microscopy (C-AFM) measurement on n-doped GaN nanowires shows good conductivity for individual nanowires, which confirms the potential of using this platform for novel device applications. By using a relatively low-temperature growth process, we were able to successfully grow high-quality single-crystal GaN material without the degradation of the underlying ITO layer.
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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
| | - Ram Chandra Subedi
- Photonics Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Malleswararao Tangi
- Photonics Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Jorge A Holguin-Lerma
- 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
| | - Davide Priante
- Photonics Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, 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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Kimura T, Sato S, Kataoka K, Morikawa T, Nakamura D. Self-Assembled Single-Crystalline GaN Having a Bimodal Meso/Macropore Structure To Enhance Photoabsorption and Photocatalytic Reactions. ACS Appl Mater Interfaces 2019; 11:4233-4241. [PMID: 30608116 DOI: 10.1021/acsami.8b18088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
This paper describes the self-assembled fabrication of single-crystal GaN with a bimodal pore (meso/macropore) size distribution (BiPS-GaN). A 4.7 μm-thick BiPS-GaN layer was grown spontaneously using halogen-free vapor phase epitaxy in conjunction with boron impurity doping (>1 × 1019 atoms/cm3) on a GaN template fabricated via metalorganic chemical vapor deposition (MOCVD-GaN). The boron impurity acted as a surfactant, and its segregation generated a dense (>1 × 1010 cm-2), homogeneous distribution of mesopores with sizes of 30-40 nm in GaN during growth. In addition, macropores with sizes of 0.1-2 μm were produced by the fusion of mesopores in close proximity to one another. As a result, BiPS-GaN exhibited a high density of both meso- and macropores, all aligned in the vertical direction (that is, along the c axis). BiPS-GaN showed good electroconductivity and almost the same high degree of crystallinity as the MOCVD-GaN template. Furthermore, the hybrid meso/macropore structure of BiPS-GaN imparted excellent photoabsorption properties and allowed this material to work as an efficient support for a nanosized IrO x catalyst. The photocurrent density in BiPS-GaN was enhanced by as much as a factor of 5 compared to planar GaN by effective absorption due to the hybrid meso/macropore structure of BiPS-GaN. Moreover, the oxygen generation efficiency of BiPS-GaN with the IrO x catalyst was approximately doubled, compared to that of BiPS-GaN without IrO x, while maintaining long-term stability. These results demonstrate that BiPS-GaN fabricated in this facile manner has significant potential in applications such as photoelectrochemical reactions and catalysis.
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Affiliation(s)
- Taishi Kimura
- Toyota Central R&D Labs., Inc. , Nagakute , Aichi 480-1192 , Japan
| | - Shunsuke Sato
- Toyota Central R&D Labs., Inc. , Nagakute , Aichi 480-1192 , Japan
| | - Keita Kataoka
- Toyota Central R&D Labs., Inc. , Nagakute , Aichi 480-1192 , Japan
| | - Takeshi Morikawa
- Toyota Central R&D Labs., Inc. , Nagakute , Aichi 480-1192 , Japan
| | - Daisuke Nakamura
- Toyota Central R&D Labs., Inc. , Nagakute , Aichi 480-1192 , Japan
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Tomida D, Kuroda K, Nakamura K, Qiao K, Yokoyama C. Temperature dependent control of the solubility of gallium nitride in supercritical ammonia using mixed mineralizer. Chem Cent J 2018; 12:127. [PMID: 30511321 PMCID: PMC6768146 DOI: 10.1186/s13065-018-0501-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 11/27/2018] [Indexed: 11/10/2022] Open
Abstract
Using a mass-loss method, we investigated the solubility change of gallium nitride (GaN) in supercritical ammonia with mixed mineralizers [ammonium chloride (NH4Cl) + ammonium bromide (NH4Br) and NH4Cl + ammonium iodide (NH4I)]. The solubilities were measured over the temperature range 450–550 °C, at 100 MPa. The solubility increased with NH4Cl mole fraction at 450 °C and 100 MPa. The temperature dependence of the solubility curve was then measured at an equal mole ratio of the two mineralizers. The slope of the solubility–temperature relationship in the mixed mineralizer was between those of the individual mineralizers. These results show that the temperature dependence of the solubility of GaN can be controlled by the mineralizer mixture ratio. The results of the van’t Hoff plot suggest that the solubility species were unchanged over the investigated temperature range. Our approach might pave the way to realizing large, high-quality GaN crystals for future gallium-nitride electronic devices, which are increasingly on demand in the information-based age.
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Affiliation(s)
- Daisuke Tomida
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan.
| | - Kiyoshi Kuroda
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Kentaro Nakamura
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Kun Qiao
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Chiaki Yokoyama
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
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Vanka S, Arca E, Cheng S, Sun K, Botton GA, Teeter G, Mi Z. High Efficiency Si Photocathode Protected by Multifunctional GaN Nanostructures. Nano Lett 2018; 18:6530-6537. [PMID: 30216079 DOI: 10.1021/acs.nanolett.8b03087] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Photoelectrochemical water splitting is a clean and environmentally friendly method for solar hydrogen generation. Its practical application, however, has been limited by the poor stability of semiconductor photoelectrodes. In this work, we demonstrate the use of GaN nanostructures as a multifunctional protection layer for an otherwise unstable, low-performance photocathode. The direct integration of GaN nanostructures on n+-p Si wafer not only protects Si surface from corrosion but also significantly reduces the charge carrier transfer resistance at the semiconductor/liquid junction, leading to long-term stability (>100 h) at a large current density (>35 mA/cm2) under 1 sun illumination. The measured applied bias photon-to-current efficiency of 10.5% is among the highest values ever reported for a Si photocathode. Given that both Si and GaN are already widely produced in industry, our studies offer a viable path for achieving high-efficiency and highly stable semiconductor photoelectrodes for solar water splitting with proven manufacturability and scalability.
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Affiliation(s)
- Srinivas Vanka
- Department of Electrical Engineering and Computer Science , University of Michigan , 1301 Beal Avenue , Ann Arbor , Michigan 48109 , United States
- Department of Electrical and Computer Engineering , McGill University , 3480 University Street , Montreal , Quebec H3A 0E9 , Canada
| | - Elisabetta Arca
- National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| | - Shaobo Cheng
- Department of Materials Science and Engineering, Canadian Centre for Electron Microscopy , McMaster University , 1280 Main Street West , Hamilton , Ontario L8S 4M1 , Canada
| | - Kai Sun
- Department of Materials Science and Engineering , University of Michigan , 2300 Hayward Street , Ann Arbor , Michigan 48109 , United States
| | - 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
| | - Glenn Teeter
- National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| | - Zetian Mi
- Department of Electrical Engineering and Computer Science , University of Michigan , 1301 Beal Avenue , Ann Arbor , Michigan 48109 , United States
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14
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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 Res Lett 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] [What about the content of this article? (0)] [Affiliation(s)] [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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15
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Abstract
Wrap-around gate GaN nanowire MOSFETs using Al2O3 as gate oxide have been experimentally demonstrated. The fabricated devices exhibit a minimum subthreshold slope of 60 mV/dec, an average subthreshold slope of 68 mV/dec over three decades of drain current, drain-induced barrier lowering of 27 mV/V, an on-current of 42 μA/μm (normalized by nanowire circumference), on/off ratio over 108, an intrinsic transconductance of 27.8 μS/μm, for a switching efficiency figure of merit, Q=gm/SS of 0.41 μS/μm-dec/mV. These performance metrics make GaN nanowire MOSFETs a promising candidate for emerging low-power applications such as sensors and RF for the internet of things.
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Affiliation(s)
- Wenjun Li
- University of Notre Dame, Notre Dame, IN 46656 USA
| | - Matt D Brubaker
- National Institute of Standards and Technology, Boulder, CO 80305 USA
| | - Bryan T Spann
- National Institute of Standards and Technology, Boulder, CO 80305 USA
| | - Kris A Bertness
- National Institute of Standards and Technology, Boulder, CO 80305 USA
| | - Patrick Fay
- University of Notre Dame, Notre Dame, IN 46656 USA
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16
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Tsykaniuk BI, Nikolenko AS, Strelchuk VV, Naseka VM, Mazur YI, Ware ME, DeCuir EA, Sadovyi B, Weyher JL, Jakiela R, Salamo GJ, Belyaev AE. Infrared Reflectance Analysis of Epitaxial n-Type Doped GaN Layers Grown on Sapphire. Nanoscale Res Lett 2017; 12:397. [PMID: 28599511 PMCID: PMC5465006 DOI: 10.1186/s11671-017-2171-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 05/30/2017] [Indexed: 06/07/2023]
Abstract
Infrared (IR) reflectance spectroscopy is applied to study Si-doped multilayer n+/n0/n+-GaN structure grown on GaN buffer with GaN-template/sapphire substrate. Analysis of the investigated structure by photo-etching, SEM, and SIMS methods showed the existence of the additional layer with the drastic difference in Si and O doping levels and located between the epitaxial GaN buffer and template. Simulation of the experimental reflectivity spectra was performed in a wide frequency range. It is shown that the modeling of IR reflectance spectrum using 2 × 2 transfer matrix method and including into analysis the additional layer make it possible to obtain the best fitting of the experimental spectrum, which follows in the evaluation of GaN layer thicknesses which are in good agreement with the SEM and SIMS data. Spectral dependence of plasmon-LO-phonon coupled modes for each GaN layer is obtained from the spectral dependence of dielectric of Si doping impurity, which is attributed to compensation effects by the acceptor states.
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Affiliation(s)
- Bogdan I Tsykaniuk
- V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, Pr. Nauky 41, Kiev, 03680, Ukraine.
| | - Andrii S Nikolenko
- V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, Pr. Nauky 41, Kiev, 03680, Ukraine
| | - Viktor V Strelchuk
- V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, Pr. Nauky 41, Kiev, 03680, Ukraine
| | - Viktor M Naseka
- V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, Pr. Nauky 41, Kiev, 03680, Ukraine
| | - Yuriy I Mazur
- Institute for Nanoscience and Engineering, University of Arkansas, West Dickson 731, Fayetteville, AR, 72701, USA
| | - Morgan E Ware
- Institute for Nanoscience and Engineering, University of Arkansas, West Dickson 731, Fayetteville, AR, 72701, USA
| | - Eric A DeCuir
- Institute for Nanoscience and Engineering, University of Arkansas, West Dickson 731, Fayetteville, AR, 72701, USA
| | - Bogdan Sadovyi
- Institute of High Pressure Physics, Polish Academy of Sciences, Sokolowska str. 29/37, 01-142, Warsaw, Poland
| | - Jan L Weyher
- Institute of High Pressure Physics, Polish Academy of Sciences, Sokolowska str. 29/37, 01-142, Warsaw, Poland
| | - Rafal Jakiela
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, PL-02-668, Warsaw, Poland
| | - Gregory J Salamo
- Institute for Nanoscience and Engineering, University of Arkansas, West Dickson 731, Fayetteville, AR, 72701, USA
| | - Alexander E Belyaev
- V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, Pr. Nauky 41, Kiev, 03680, Ukraine
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17
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Wellmann PJ. Power Electronic Semiconductor Materials for Automotive and Energy Saving Applications - SiC, GaN, Ga 2O 3, and Diamond. Z Anorg Allg Chem 2017; 643:1312-1322. [PMID: 29200530 PMCID: PMC5698769 DOI: 10.1002/zaac.201700270] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Indexed: 11/10/2022]
Abstract
Power electronics belongs to the future key technologies in order to increase system efficiency as well as performance in automotive and energy saving applications. Silicon is the major material for electronic switches since decades. Advanced fabrication processes and sophisticated electronic device designs have optimized the silicon electronic device performance almost to their theoretical limit. Therefore, to increase the system performance, new materials that exhibit physical and chemical properties beyond silicon need to be explored. A number of wide bandgap semiconductors like silicon carbide, gallium nitride, gallium oxide, and diamond exhibit outstanding characteristics that may pave the way to new performance levels. The review will introduce these materials by (i) highlighting their properties, (ii) introducing the challenges in materials growth, and (iii) outlining limits that need innovation steps in materials processing to outperform current technologies.
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Affiliation(s)
- Peter J Wellmann
- Crystal Growth Lab Materials Department 6 (i-meet) Friedrich-Alexander University of Erlangen-Nürnberg Martensstr. 7 91058 Erlangen Germany
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18
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Braniste T, Tiginyanu I, Horvath T, Raevschi S, Andrée B, Cebotari S, Boyle EC, Haverich A, Hilfiker A. Targeting Endothelial Cells with Multifunctional GaN/Fe Nanoparticles. Nanoscale Res Lett 2017; 12:486. [PMID: 28799116 PMCID: PMC5552623 DOI: 10.1186/s11671-017-2262-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 08/01/2017] [Indexed: 06/07/2023]
Abstract
In this paper, we report on the interaction of multifunctional nanoparticles with living endothelial cells. The nanoparticles were synthesized using direct growth of gallium nitride on zinc oxide nanoparticles alloyed with iron oxide followed by core decomposition in hydrogen flow at high temperature. Using transmission electron microscopy, we demonstrate that porcine aortic endothelial cells take up GaN-based nanoparticles suspended in the growth medium. The nanoparticles are deposited in vesicles and the endothelial cells show no sign of cellular damage. Intracellular inert nanoparticles are used as guiding elements for controlled transportation or designed spatial distribution of cells in external magnetic fields.
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Affiliation(s)
- Tudor Braniste
- National Center for Materials Study and Testing, Technical University of Moldova, Stefan cel Mare av. 168, MD-2004 Chisinau, Republic of Moldova
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
| | - Ion Tiginyanu
- National Center for Materials Study and Testing, Technical University of Moldova, Stefan cel Mare av. 168, MD-2004 Chisinau, Republic of Moldova
| | - Tibor Horvath
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
| | - Simion Raevschi
- Department of Physics and Engineering, State University of Moldova, str. Alexei Mateevici 60, Chisinau, MD-2009 Republic of Moldova
| | - Birgit Andrée
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
| | - Serghei Cebotari
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
| | - Erin C. Boyle
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
| | - Axel Haverich
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
| | - Andres Hilfiker
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
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19
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Abstract
GaN is a key material for lighting technology. Yet, the carrier transport and ultrafast dynamics that are central in GaN light-emitting devices are not completely understood. We present first-principles calculations of carrier dynamics in GaN, focusing on electron-phonon (e-ph) scattering and the cooling and nanoscale dynamics of hot carriers. We find that e-ph scattering is significantly faster for holes compared to electrons and that for hot carriers with an initial 0.5-1 eV excess energy, holes take a significantly shorter time (∼0.1 ps) to relax to the band edge compared to electrons, which take ∼1 ps. The asymmetry in the hot carrier dynamics is shown to originate from the valence band degeneracy, the heavier effective mass of holes compared to electrons, and the details of the coupling to different phonon modes in the valence and conduction bands. We show that the slow cooling of hot electrons and their long ballistic mean free paths (over 3 nm at room temperature) are a possible cause of efficiency droop in GaN light-emitting diodes. Taken together, our work sheds light on the ultrafast dynamics of hot carriers in GaN and the nanoscale origin of efficiency droop.
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Affiliation(s)
- Vatsal A Jhalani
- Department of Applied Physics and Materials Science, Steele Laboratory, California Institute of Technology , Pasadena, California 91125, United States
| | - Jin-Jian Zhou
- Department of Applied Physics and Materials Science, Steele Laboratory, California Institute of Technology , Pasadena, California 91125, United States
| | - Marco Bernardi
- Department of Applied Physics and Materials Science, Steele Laboratory, California Institute of Technology , Pasadena, California 91125, United States
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20
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Jiang QM, Zhang MR, Luo LQ, Pan GB. Electrosynthesis of bismuth nanodendrites/ gallium nitride electrode for non-enzymatic hydrogen peroxide detection. Talanta 2017; 171:250-254. [PMID: 28551137 DOI: 10.1016/j.talanta.2017.04.075] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 04/21/2017] [Accepted: 04/30/2017] [Indexed: 01/08/2023]
Abstract
Bismuth nanodendrites (BiNDs) were electrodeposited on planar gallium nitride (GaN) electrode via a differential pulse voltammetric technique to fabricate the non-enzymatic hydrogen peroxide (H2O2) sensor. SEM images revealed that the as-obtained BiNDs had numerous dendrite sub-branches, whose diameters ranged from 136 to 152nm. The BiNDs/GaN electrode showed linear amperometric responses for H2O2 in the concentration range from 10µM to 1mM with the sensitivity of 60.0μAmM-1cm-2. Another linear range was from 1 to 10mM with the sensitivity of 23.3μAmM-1cm-2. The limit of detection (LOD) was 5µM with the signal-to-noise ratio of 3. The applicability of the sensor was investigated to the H2O2 detection in real samples such as fetal bovine serum and milk, and the sensor exhibited excellent anti-interference capacity. The achieved results indicate that the as-prepared BiNDs/GaN sensor with good reproducibility and long-term stability was promising for detecting H2O2 in practical environments.
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Affiliation(s)
- Qing-Mei Jiang
- Department of Chemistry, College of Sciences, Shanghai University, 99 Shangda Road, 200444 Shanghai, PR China; Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 215123 Suzhou, PR China
| | - Miao-Rong Zhang
- Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 215123 Suzhou, PR China; University of Chinese Academy of Sciences, 100049 Beijing, PR China
| | - Li-Qiang Luo
- Department of Chemistry, College of Sciences, Shanghai University, 99 Shangda Road, 200444 Shanghai, PR China
| | - Ge-Bo Pan
- Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 215123 Suzhou, PR China
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21
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Jung BO, Bae SY, Lee S, Kim SY, Lee JY, Honda Y, Amano H. Emission Characteristics of InGaN/GaN Core-Shell Nanorods Embedded in a 3D Light-Emitting Diode. Nanoscale Res Lett 2016; 11:215. [PMID: 27102904 PMCID: PMC4840131 DOI: 10.1186/s11671-016-1441-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 04/15/2016] [Indexed: 05/16/2023]
Abstract
We report the selective-area growth of a gallium nitride (GaN)-nanorod-based InGaN/GaN multiple-quantum-well (MQW) core-shell structure embedded in a three-dimensional (3D) light-emitting diode (LED) grown by metalorganic chemical vapor deposition (MOCVD) and its optical analysis. High-resolution transmission electron microscopy (HR-TEM) observation revealed the high quality of the GaN nanorods and the position dependence of the structural properties of the InGaN/GaN MQWs on multiple facets. The excitation and temperature dependences of photoluminescence (PL) revealed the m-plane emission behaviors of the InGaN/GaN core-shell nanorods. The electroluminescence (EL) of the InGaN/GaN core-shell-nanorod-embedded 3D LED changed color from green to blue with increasing injection current. This phenomenon was mainly due to the energy gradient and deep localization of the indium in the selectively grown InGaN/GaN core-shell MQWs on the 3D architecture.
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Affiliation(s)
- Byung Oh Jung
- />Department of Electrical Engineering and Computer Science, Nagoya University, Nagoya, Aichi 464-8603 Japan
- />Akasaki Research Center (ARC), Nagoya University, Nagoya, Aichi 464-8603 Japan
| | - Si-Young Bae
- />Akasaki Research Center (ARC), Nagoya University, Nagoya, Aichi 464-8603 Japan
- />Center for Integrated Research of Future Electronics (CIRFE), Institute of Materials and Systems for Sustainability (IMaSS), Nagoya University, Nagoya, Aichi 464-8603 Japan
| | - Seunga Lee
- />Department of Electrical Engineering and Computer Science, Nagoya University, Nagoya, Aichi 464-8603 Japan
- />Akasaki Research Center (ARC), Nagoya University, Nagoya, Aichi 464-8603 Japan
| | - Sang Yun Kim
- />Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon, 305-701 Korea
- />Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701 Korea
| | - Jeong Yong Lee
- />Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon, 305-701 Korea
- />Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701 Korea
| | - Yoshio Honda
- />Akasaki Research Center (ARC), Nagoya University, Nagoya, Aichi 464-8603 Japan
- />Center for Integrated Research of Future Electronics (CIRFE), Institute of Materials and Systems for Sustainability (IMaSS), Nagoya University, Nagoya, Aichi 464-8603 Japan
| | - Hiroshi Amano
- />Akasaki Research Center (ARC), Nagoya University, Nagoya, Aichi 464-8603 Japan
- />Center for Integrated Research of Future Electronics (CIRFE), Institute of Materials and Systems for Sustainability (IMaSS), Nagoya University, Nagoya, Aichi 464-8603 Japan
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22
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Kumaresan V, Largeau L, Madouri A, Glas F, Zhang H, Oehler F, Cavanna A, Babichev A, Travers L, Gogneau N, Tchernycheva M, Harmand JC. Epitaxy of GaN Nanowires on Graphene. Nano Lett 2016; 16:4895-4902. [PMID: 27414518 DOI: 10.1021/acs.nanolett.6b01453] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Epitaxial growth of GaN nanowires on graphene is demonstrated using molecular beam epitaxy without any catalyst or intermediate layer. Growth is highly selective with respect to silica on which the graphene flakes, grown by chemical vapor deposition, are transferred. The nanowires grow vertically along their c-axis and we observe a unique epitaxial relationship with the ⟨21̅1̅0⟩ directions of the wurtzite GaN lattice parallel to the directions of the carbon zigzag chains. Remarkably, the nanowire density and height decrease with increasing number of graphene layers underneath. We attribute this effect to strain and we propose a model for the nanowire density variation. The GaN nanowires are defect-free and they present good optical properties. This demonstrates that graphene layers transferred on amorphous carrier substrates is a promising alternative to bulk crystalline substrates for the epitaxial growth of high quality GaN nanostructures.
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Affiliation(s)
- Vishnuvarthan Kumaresan
- Laboratoire de Photonique et de Nanostructures (LPN), CNRS, Université Paris-Saclay, Route de Nozay , F-91460 Marcoussis, France
| | - Ludovic Largeau
- Laboratoire de Photonique et de Nanostructures (LPN), CNRS, Université Paris-Saclay, Route de Nozay , F-91460 Marcoussis, France
| | - Ali Madouri
- Laboratoire de Photonique et de Nanostructures (LPN), CNRS, Université Paris-Saclay, Route de Nozay , F-91460 Marcoussis, France
| | - Frank Glas
- Laboratoire de Photonique et de Nanostructures (LPN), CNRS, Université Paris-Saclay, Route de Nozay , F-91460 Marcoussis, France
| | - Hezhi Zhang
- Institut d'Electronique Fondamentale, UMR 8622 CNRS, University Paris Sud, University Paris-Saclay , 91405 Orsay cedex, France
| | - Fabrice Oehler
- Laboratoire de Photonique et de Nanostructures (LPN), CNRS, Université Paris-Saclay, Route de Nozay , F-91460 Marcoussis, France
| | - Antonella Cavanna
- Laboratoire de Photonique et de Nanostructures (LPN), CNRS, Université Paris-Saclay, Route de Nozay , F-91460 Marcoussis, France
| | - Andrey Babichev
- Institut d'Electronique Fondamentale, UMR 8622 CNRS, University Paris Sud, University Paris-Saclay , 91405 Orsay cedex, France
- ITMO University , St. Petersburg 197101, Russia
| | - Laurent Travers
- Laboratoire de Photonique et de Nanostructures (LPN), CNRS, Université Paris-Saclay, Route de Nozay , F-91460 Marcoussis, France
| | - Noelle Gogneau
- Laboratoire de Photonique et de Nanostructures (LPN), CNRS, Université Paris-Saclay, Route de Nozay , F-91460 Marcoussis, France
| | - Maria Tchernycheva
- Institut d'Electronique Fondamentale, UMR 8622 CNRS, University Paris Sud, University Paris-Saclay , 91405 Orsay cedex, France
| | - Jean-Christophe Harmand
- Laboratoire de Photonique et de Nanostructures (LPN), CNRS, Université Paris-Saclay, Route de Nozay , F-91460 Marcoussis, France
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23
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Gamalski AD, Tersoff J, Stach EA. Atomic Resolution in Situ Imaging of a Double-Bilayer Multistep Growth Mode in Gallium Nitride Nanowires. Nano Lett 2016; 16:2283-8. [PMID: 26990711 DOI: 10.1021/acs.nanolett.5b04650] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We study the growth of GaN nanowires from liquid Au-Ga catalysts using environmental transmission electron microscopy. GaN wires grow in either ⟨112̅0⟩ or ⟨11̅00⟩ directions, by the addition of {11̅00} double bilayers via step flow with multiple steps. Step-train growth is not typically seen with liquid catalysts, and we suggest that it results from low step mobility related to the unusual double-height step structure. The results here illustrate the surprising dynamics of catalytic GaN wire growth at the nanoscale and highlight striking differences between the growth of GaN and other III-V semiconductor nanowires.
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Affiliation(s)
- A D Gamalski
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States
| | - J Tersoff
- IBM Research Division, T. J. Watson Research Center , Yorktown Heights, New York 10598, United States
| | - E A Stach
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States
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24
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Bain LE, Kirste R, Johnson CA, Ghashghaei HT, Collazo R, Ivanisevic A. Neurotypic cell attachment and growth on III-nitride lateral polarity structures. Mater Sci Eng C Mater Biol Appl 2015; 58:1194-8. [PMID: 26478421 DOI: 10.1016/j.msec.2015.09.084] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 09/01/2015] [Accepted: 09/23/2015] [Indexed: 01/24/2023]
Abstract
III-nitride materials have recently received increasing levels of attention for their potential to successfully interface with, and sense biochemical interactions in biological systems. Expanding on available sensing schemes (including transistor-based devices,) a III-N lateral polarity structure capable of introducing quasi-phase matching through a periodic polarity grating presents a novel platform for second harmonic generation. This platform constitutes a non-linear optical phenomenon with exquisite sensitivity to the chemical state of a surface or interface. To characterize the response of a biological system to the nanostructured lateral polarity structures, we cultured neurotypic PC12 cells on AlGaN with varying ratios of Al:Ga - 0, 0.4, 0.6, and 1 - and on surfaces of varying pitch to the III-polar vs. N-polar grating - 5, 10, 20 and 50 μm. While some toxicity associated with increasing Al is observed, we documented and quantified trends in cell responses to the local material polarity and nanoscale roughness. The nitrogen-polar material has a significantly higher nanoscale roughness than III-polar regions, and a 80-200 nm step height difference between the III-polar and N-polar materials in the lateral polarity configuration generates adequate changes in topography to influence cell growth, improves cell adhesion and promotes cell migration along the direction of the features. As the designed material configuration is further explored for biochemical sensing, the lateral polarity scheme may provide a route in assessing the non-specific protein adsorption to this varying nano-topography that drives the subsequent cell response.
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Affiliation(s)
- L E Bain
- UNC/NCSU Joint Department of Biomedical Engineering, North Carolina State University, Raleigh, NC, United States
| | - R Kirste
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, United States
| | - C A Johnson
- Department of Molecular Biomedical Sciences, Center for Comparative Medicine and Translational Research, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, United States
| | - H T Ghashghaei
- Department of Molecular Biomedical Sciences, Center for Comparative Medicine and Translational Research, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, United States
| | - R Collazo
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, United States
| | - A Ivanisevic
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, United States.
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Chiang YC, Lin CC, Kuo HC. Novel thin-GaN LED structure adopted micro abraded surface to compare with conventional vertical LEDs in ultraviolet light. Nanoscale Res Lett 2015; 10:182. [PMID: 25977655 PMCID: PMC4404426 DOI: 10.1186/s11671-015-0885-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 03/28/2015] [Indexed: 05/26/2023]
Abstract
In this study, novel thin-GaN-based ultraviolet light-emitting diodes (NTG-LEDs) were fabricated using wafer bonding, laser lift-off, dry etching, textured surface, and interconnection techniques. Placing PN electrodes on the same side minimized the absorption caused by electrodes in conventional vertical injection light-emitting diodes (V-LEDs) and the current spreading was improved. The light output power (700 mA) of the NTG-LEDs was enhanced by 18.3% compared with that of the V-LEDs, and the external quantum efficiency (EQE) of the NTG-LEDs was also relatively enhanced by 20.0% compared with that of a reference device. When the current operations were 1,500 mA, the enhancements of the light output power and EQE were 27.4% and 27.2%, respectively. Additionally, the efficiency droop was improved by more than 15% at the same current level.
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Affiliation(s)
- Yen Chih Chiang
- />Institute of Lighting and Energy Photonics, National Chiao Tung University, No.301, Gaofa 3rd Rd., Guiren Dist., Tainan City, 71150 Taiwan
| | - Chien Chung Lin
- />Institute of Photonic System, National Chiao Tung University, No.301, Gaofa 3rd Rd., Guiren Dist., Tainan City, 71150 Taiwan
| | - Hao Chung Kuo
- />Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, 1001 University Road, Hsinchu, 300 Taiwan
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26
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Yesinowski JP. Finding the true spin-lattice relaxation time for half-integral nuclei with non-zero quadrupole couplings. J Magn Reson 2015; 252:135-144. [PMID: 25700115 DOI: 10.1016/j.jmr.2014.12.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 12/17/2014] [Accepted: 12/23/2014] [Indexed: 06/04/2023]
Abstract
Measuring true spin-lattice relaxation times T(1) of half-integral quadrupolar nuclei having non-zero nuclear quadrupole coupling constants (NQCCs) presents challenges due to the presence of satellite-transitions (STs) that may lie outside the excitation bandwidth of the central transition (CT). This leads to complications in establishing well-defined initial conditions for the population differences in these multi-level systems. In addition, experiments involving magic-angle spinning (MAS) can introduce spin exchange due to zero-crossings of the ST and CT (or possibly rotational resonance recoupling in the case of multiple sites) and greatly altered initial conditions as well. An extensive comparison of pulse sequences that have been previously used to measure T(1) in such systems is reported, using the (71)Ga (I=3/2) NMR of a Ge-doped h-GaN n-type semiconductor sample as the test case. The T(1) values were measured at the peak maximum of the Knight shift distribution. Analytical expressions for magnetization-recovery of the CT appropriate to the pulse sequences tested were used, involving contributions from both a magnetic relaxation mechanism (rate constant W) and a quadrupolar one (rate constants W(1) and W(2), approximately equal in this case). An asynchronous train of high-power saturating pulses under MAS that is able to completely saturate both CT and STs is found to be the most reliable and accurate method for obtaining the "true T(1)", defined here as (2W+2W1,2)(-)(1). All other methods studied yielded poor agreement with this "true T(1)" value or even resulted in gross errors, for reasons that are analyzed in detail. These methods involved a synchronous train of saturating pulses under MAS, an inversion-recovery sequence under MAS or static conditions, and a saturating comb of pulses on a static sample. Although the present results were obtained on a sample where the magnetic relaxation mechanism dominated the quadrupolar one, the asynchronous saturating pulse train approach is not limited to this situation. The extent to which W(1) and W(2) are unequal does affect the interpretability of the experiment however, particularly when the quadrupolar mechanism dominates. A numerically approximate solution for the I=3/2 recovery case reveals the quantitative effects of any such inequality.
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Affiliation(s)
- James P Yesinowski
- Chemistry Division, Naval Research Laboratory, Washington, DC 20375-5342, USA.
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Ghazali NM, Yasui K, Hashim AM. Synthesis of gallium nitride nanostructures by nitridation of electrochemically deposited gallium oxide on silicon substrate. Nanoscale Res Lett 2014; 9:685. [PMID: 25593562 PMCID: PMC4273690 DOI: 10.1186/1556-276x-9-685] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 12/09/2014] [Indexed: 06/04/2023]
Abstract
Gallium nitride (GaN) nanostructures were successfully synthesized by the nitridation of the electrochemically deposited gallium oxide (Ga2O3) through the utilization of a so-called ammoniating process. Ga2O3 nanostructures were firstly deposited on Si substrate by a simple two-terminal electrochemical technique at a constant current density of 0.15 A/cm(2) using a mixture of Ga2O3, HCl, NH4OH and H2O for 2 h. Then, the deposited Ga2O3 sample was ammoniated in a horizontal quartz tube single zone furnace at various ammoniating times and temperatures. The complete nitridation of Ga2O3 nanostructures at temperatures of 850°C and below was not observed even the ammoniating time was kept up to 45 min. After the ammoniating process at temperature of 900°C for 15 min, several prominent diffraction peaks correspond to hexagonal GaN (h-GaN) planes were detected, while no diffraction peak of Ga2O3 structure was detected, suggesting a complete transformation of Ga2O3 to GaN. Thus, temperature seems to be a key parameter in a nitridation process where the deoxidization rate of Ga2O3 to generate gaseous Ga2O increase with temperature. The growth mechanism for the transformation of Ga2O3 to GaN was proposed and discussed. It was found that a complete transformation can not be realized without a complete deoxidization of Ga2O3. A significant change of morphological structures takes place after a complete transformation of Ga2O3 to GaN where the original nanorod structures of Ga2O3 diminish, and a new nanowire-like GaN structures appear. These results show that the presented method seems to be promising in producing high-quality h-GaN nanostructures on Si.
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Affiliation(s)
- Norizzawati Mohd Ghazali
- Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Semarak, 54100 Kuala Lumpur, Malaysia
| | - Kanji Yasui
- Department of Electrical Engineering, Nagaoka University of Technology, Kamitomioka-machi, Nagaoka, Niigata 940-2137, Japan
| | - Abdul Manaf Hashim
- Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Semarak, 54100 Kuala Lumpur, Malaysia
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Yu IS, Chang CP, Yang CP, Lin CT, Ma YR, Chen CC. Characterization and density control of GaN nanodots on Si (111) by droplet epitaxy using plasma-assisted molecular beam epitaxy. Nanoscale Res Lett 2014; 9:682. [PMID: 25593560 PMCID: PMC4275119 DOI: 10.1186/1556-276x-9-682] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 12/12/2014] [Indexed: 06/04/2023]
Abstract
In this report, self-organized GaN nanodots have been grown on Si (111) by droplet epitaxy method, and their density can be controlled from 1.1 × 10(10) to 1.1 × 10(11) cm(-2) by various growth parameters, such as substrate temperatures for Ga droplet formation, the pre-nitridation treatment of Si substrate, the nitridation duration for GaN crystallization, and in situ annealing after GaN formation. Based on the characterization of in situ RHEED, we can observe the surface condition of Si and the formation of GaN nanodots on Si. The surface nitridaiton treatment at 600°C provides a-SiNx layer which makes higher density of GaN nanodots. Crystal GaN nanodots can be observed by the HRTEM. The surface composition of GaN nanodots can be analyzed by SPEM and μ-XPS with a synchrotron x-ray source. We can find GaN nanodots form by droplet epitaxy and then in situ annealing make higher-degree nitridation of GaN nanodots.
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Affiliation(s)
- Ing-Song Yu
- Department of Materials Science and Engineering, National Dong Hwa University, Hualien 97401, Taiwan
| | - Chun-Pu Chang
- Institute of Photonic System, National Chiao Tung University, Tainan 71150, Taiwan
| | - Chung-Pei Yang
- Institute of Photonic System, National Chiao Tung University, Tainan 71150, Taiwan
| | - Chun-Ting Lin
- Institute of Photonic System, National Chiao Tung University, Tainan 71150, Taiwan
| | - Yuan-Ron Ma
- Department of Physics, National Dong Hwa University, Hualien 97401, Taiwan
| | - Chun-Chi Chen
- National Nano Device Laboratories, Hsinchu 30078, Taiwan
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Bain LE, Collazo R, Hsu SH, Latham NP, Manfra MJ, Ivanisevic A. Surface topography and chemistry shape cellular behavior on wide band-gap semiconductors. Acta Biomater 2014; 10:2455-62. [PMID: 24590161 DOI: 10.1016/j.actbio.2014.02.038] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 01/17/2014] [Accepted: 02/21/2014] [Indexed: 01/08/2023]
Abstract
The chemical stability and electrical properties of gallium nitride make it a promising material for the development of biocompatible electronics, a range of devices including biosensors as well as interfaces for probing and controlling cellular growth and signaling. To improve the interface formed between the probe material and the cell or biosystem, surface topography and chemistry can be applied to modify the ways in which the device interacts with its environment. PC12 cells are cultured on as-grown planar, unidirectionally polished, etched nanoporous and nanowire GaN surfaces with and without a physisorbed peptide sequence that promotes cell adhesion. While cells demonstrate preferential adhesion to roughened surfaces over as-grown flat surfaces, the topography of that roughness also influences the morphology of cellular adhesion and differentiation in neurotypic cells. Addition of the peptide sequence generally contributes further to cellular adhesion and promotes development of stereotypic long, thin neurite outgrowths over alternate morphologies. The dependence of cell behavior on both the topographic morphology and surface chemistry is thus demonstrated, providing further evidence for the importance of surface modification for modulating bio-inorganic interfaces.
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