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AlGaN Quantum Disk Nanorods with Efficient UV-B Emission Grown on Si(111) Using Molecular Beam Epitaxy. NANOMATERIALS 2022; 12:nano12142508. [PMID: 35889730 PMCID: PMC9319290 DOI: 10.3390/nano12142508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/20/2022] [Accepted: 07/20/2022] [Indexed: 11/17/2022]
Abstract
AlGaN nanorods have attracted increasing amounts of attention for use in ultraviolet (UV) optoelectronic devices. Here, self-assembled AlGaN nanorods with embedding quantum disks (Qdisks) were grown on Si(111) using plasma-assisted molecular beam epitaxy (PA-MBE). The morphology and quantum construction of the nanorods were investigated and well-oriented and nearly defect-free nanorods were shown to have a high density of about 2 × 1010 cm−2. By controlling the substrate temperature and Al/Ga ratio, the emission wavelengths of the nanorods could be adjusted from 276 nm to 330 nm. By optimizing the structures and growth parameters of the Qdisks, a high internal quantum efficiency (IQE) of the AlGaN Qdisk nanorods of up to 77% was obtained at 305 nm, which also exhibited a shift in the small emission wavelength peak with respect to the increasing temperatures during the PL measurements.
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2
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Sarkar R, Bhunia S, Jana D, Nag D, Chatterjee S, Laha A. Growth of uniform Mg-doped p-AlGaN nanowires using plasma-assisted molecular beam epitaxy technique for UV-A emitters. NANOTECHNOLOGY 2022; 33:384001. [PMID: 35636220 DOI: 10.1088/1361-6528/ac7472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
In this manuscript, we have shown the growth and extensive structural and optical characteristic of the uniformly Mg-doped Al0.23Ga0.77N (UV-A region,λ∼ 323 nm) nanowire. The Kelvin probe force microscopy was employed to determine the profile of holes in p-type AlGaN nanowires by measuring the work function changes induced by Mg incorporation. The influence of surface band bending on doping concentration has thoroughly been discussed. Our experiment confirms the homogeneous incorporation of Mg throughout the nanowire without any top surface Mg segregation. In this work, we have also demonstrated a comprehensive analysis of acceptor states induced thermal quenching behaviour in the optical transition of Mg-doped AlGaN nanowire. We propose a phenomenological model, based on the rate equation which confirms that achieving higher 'hole' (p-doping) concentration in AlGaN nanowire (>1018cm-3) is more conducive than the planar counterpart if the growth of NWs is carried out at optimized process conditions. This rate equation-based model has also demonstrated the influence of sidewall surface passivation in those AlGaN nanowires.
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Affiliation(s)
- Ritam Sarkar
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai-400076, India
| | - Swagata Bhunia
- Department of Physics, Indian Institute of Technology Bombay, Mumbai-400076, India
| | - Dipankar Jana
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
| | - Dhiman Nag
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai-400076, India
| | - Soumyadip Chatterjee
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai-400076, India
| | - Apurba Laha
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai-400076, India
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3
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Daudin B, Siladie AM, Gruart M, den Hertog M, Bougerol C, Haas B, Rouvière JL, Robin E, Recio-Carretero MJ, Garro N, Cros A. The role of surface diffusion in the growth mechanism of III-nitride nanowires and nanotubes. NANOTECHNOLOGY 2021; 32:085606. [PMID: 33147580 DOI: 10.1088/1361-6528/abc780] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The spontaneous growth of GaN nanowires (NWs) in absence of catalyst is controlled by the Ga flux impinging both directly on the top and on the side walls and diffusing to the top. The presence of diffusion barriers on the top surface and at the frontier between the top and the sidewalls, however, causes an inhomogeneous distribution of Ga adatoms at the NW top surface resulting in a GaN accumulation in its periphery. The increased nucleation rate in the periphery promotes the spontaneous formation of superlattices in InGaN and AlGaN NWs. In the case of AlN NWs, the presence of Mg can enhance the otherwise short Al diffusion length along the sidewalls inducing the formation of AlN nanotubes.
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Affiliation(s)
- Bruno Daudin
- Univ. Grenoble Alpes, CEA, IRIG-PHELIQS, NPSC, 17 rue des martyrs, F-38000 Grenoble, France
| | | | - Marion Gruart
- Univ. Grenoble Alpes, CEA, IRIG-PHELIQS, NPSC, 17 rue des martyrs, F-38000 Grenoble, France
| | - Martien den Hertog
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 25 rue des martyrs, F-38000 Grenoble, France
| | - Catherine Bougerol
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 25 rue des martyrs, F-38000 Grenoble, France
| | - Benedikt Haas
- Univ. Grenoble Alpes, CEA, IRIG-MEM, LEMMA, 17 rue des martyrs, F-38000 Grenoble, France
| | - Jean-Luc Rouvière
- Univ. Grenoble Alpes, CEA, IRIG-MEM, LEMMA, 17 rue des martyrs, F-38000 Grenoble, France
| | - Eric Robin
- Univ. Grenoble Alpes, CEA, IRIG-MEM, LEMMA, 17 rue des martyrs, F-38000 Grenoble, France
| | | | - Núria Garro
- Institute of Materials Science (ICMUV), Universidad de Valencia, PO Box E-22085, Valencia, Spain
| | - Ana Cros
- Institute of Materials Science (ICMUV), Universidad de Valencia, PO Box E-22085, Valencia, Spain
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4
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Magalhães S, Cabaço JS, Mateus R, Faye DN, Pereira DR, Peres M, Lorenz K, Díaz-Guerra C, Araújo JP, Alves E. Crystal mosaicity determined by a novel layer deconvolution Williamson–Hall method. CrystEngComm 2021. [DOI: 10.1039/d0ce01669a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An improvement to the classical Williamson–Hall method is developed to study several samples of AlGaN and α-MoO3.
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Affiliation(s)
- S. Magalhães
- IPFN, Instituto de Plasmas e Fusão Nuclear
- Campus Tecnológico e Nuclear
- Instituto Superior Técnico
- Universidade de Lisboa
- 2695-066 Bobadela LRS
| | - J. S. Cabaço
- IFIMUP/IN, Instituto de Física dos Materiais da Faculdade de Ciências da Universidade do Porto, Instituto de Nanociência e Nanotecnologia
- 687 4169-007 Porto
- Portugal
| | - R. Mateus
- IPFN, Instituto de Plasmas e Fusão Nuclear
- Campus Tecnológico e Nuclear
- Instituto Superior Técnico
- Universidade de Lisboa
- 2695-066 Bobadela LRS
| | - D. Nd. Faye
- IPFN, Instituto de Plasmas e Fusão Nuclear
- Campus Tecnológico e Nuclear
- Instituto Superior Técnico
- Universidade de Lisboa
- 2695-066 Bobadela LRS
| | - D. R. Pereira
- IPFN, Instituto de Plasmas e Fusão Nuclear
- Campus Tecnológico e Nuclear
- Instituto Superior Técnico
- Universidade de Lisboa
- 2695-066 Bobadela LRS
| | - M. Peres
- IPFN, Instituto de Plasmas e Fusão Nuclear
- Campus Tecnológico e Nuclear
- Instituto Superior Técnico
- Universidade de Lisboa
- 2695-066 Bobadela LRS
| | - K. Lorenz
- IPFN, Instituto de Plasmas e Fusão Nuclear
- Campus Tecnológico e Nuclear
- Instituto Superior Técnico
- Universidade de Lisboa
- 2695-066 Bobadela LRS
| | - C. Díaz-Guerra
- Departamento de Física de Materiales
- Facultad de Ciencias Físicas
- Universidad Complutense de Madrid
- Madrid
- Spain
| | - J. P. Araújo
- IFIMUP/IN, Instituto de Física dos Materiais da Faculdade de Ciências da Universidade do Porto, Instituto de Nanociência e Nanotecnologia
- 687 4169-007 Porto
- Portugal
| | - E. Alves
- IPFN, Instituto de Plasmas e Fusão Nuclear
- Campus Tecnológico e Nuclear
- Instituto Superior Técnico
- Universidade de Lisboa
- 2695-066 Bobadela LRS
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5
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Liu M, Tan L, Zhou B, Li L, Mi Z, Li CJ. Group-III Nitrides Catalyzed Transformations of Organic Molecules. Chem 2021. [DOI: 10.1016/j.chempr.2020.09.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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6
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Sinito C, Corfdir P, Pfüller C, Gao G, Bartolomé J, Kölling S, Rodil Doblado A, Jahn U, Lähnemann J, Auzelle T, Zettler JK, Flissikowski T, Koenraad P, Grahn HT, Geelhaar L, Fernández-Garrido S, Brandt O. Absence of Quantum-Confined Stark Effect in GaN Quantum Disks Embedded in (Al,Ga)N Nanowires Grown by Molecular Beam Epitaxy. NANO LETTERS 2019; 19:5938-5948. [PMID: 31385709 DOI: 10.1021/acs.nanolett.9b01521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Several of the key issues of planar (Al,Ga)N-based deep-ultraviolet light-emitting diodes could potentially be overcome by utilizing nanowire heterostructures, exhibiting high structural perfection, and improved light extraction. Here, we study the spontaneous emission of GaN/(Al,Ga)N nanowire ensembles grown on Si(111) by plasma-assisted molecular beam epitaxy. The nanowires contain single GaN quantum disks embedded in long (Al,Ga)N nanowire segments essential for efficient light extraction. These quantum disks are found to exhibit intense light emission at unexpectedly high energies, namely, significantly above the GaN bandgap, and almost independent of the disk thickness. An in-depth investigation of the actual structure and composition of the nanowires reveals a spontaneously formed Al gradient both along and across the nanowire, resulting in a complex core/shell structure with an Al-deficient core and an Al-rich shell with continuously varying Al content along the entire length of the (Al,Ga)N segment. This compositional change along the nanowire growth axis induces a polarization doping of the shell that results in a degenerate electron gas in the disk, thus screening the built-in electric fields. The high carrier density not only results in the unexpectedly high transition energies but also in radiative lifetimes depending only weakly on temperature, leading to a comparatively high internal quantum efficiency of the GaN quantum disks up to room temperature.
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Affiliation(s)
- C Sinito
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - P Corfdir
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - C Pfüller
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - G Gao
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - J Bartolomé
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - S Kölling
- Department of Applied Physics , TU Eindhoven , Den Dolech 2 , 5612 Eindhoven , AZ , The Netherlands
| | - A Rodil Doblado
- Department of Applied Physics , TU Eindhoven , Den Dolech 2 , 5612 Eindhoven , AZ , The Netherlands
| | - U Jahn
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - J Lähnemann
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - T Auzelle
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - J K Zettler
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - T Flissikowski
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - P Koenraad
- Department of Applied Physics , TU Eindhoven , Den Dolech 2 , 5612 Eindhoven , AZ , The Netherlands
| | - H T Grahn
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - L Geelhaar
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - S Fernández-Garrido
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - O Brandt
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
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Barrigón E, Heurlin M, Bi Z, Monemar B, Samuelson L. Synthesis and Applications of III-V Nanowires. Chem Rev 2019; 119:9170-9220. [PMID: 31385696 DOI: 10.1021/acs.chemrev.9b00075] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Low-dimensional semiconductor materials structures, where nanowires are needle-like one-dimensional examples, have developed into one of the most intensely studied fields of science and technology. The subarea described in this review is compound semiconductor nanowires, with the materials covered limited to III-V materials (like GaAs, InAs, GaP, InP,...) and III-nitride materials (GaN, InGaN, AlGaN,...). We review the way in which several innovative synthesis methods constitute the basis for the realization of highly controlled nanowires, and we combine this perspective with one of how the different families of nanowires can contribute to applications. One reason for the very intense research in this field is motivated by what they can offer to main-stream semiconductors, by which ultrahigh performing electronic (e.g., transistors) and photonic (e.g., photovoltaics, photodetectors or LEDs) technologies can be merged with silicon and CMOS. Other important aspects, also covered in the review, deals with synthesis methods that can lead to dramatic reduction of cost of fabrication and opportunities for up-scaling to mass production methods.
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Affiliation(s)
- Enrique Barrigón
- Division of Solid State Physics and NanoLund , Lund University , Box 118, 22100 Lund , Sweden
| | - Magnus Heurlin
- Division of Solid State Physics and NanoLund , Lund University , Box 118, 22100 Lund , Sweden.,Sol Voltaics AB , Scheelevägen 63 , 223 63 Lund , Sweden
| | - Zhaoxia Bi
- Division of Solid State Physics and NanoLund , Lund University , Box 118, 22100 Lund , Sweden
| | - Bo Monemar
- Division of Solid State Physics and NanoLund , Lund University , Box 118, 22100 Lund , Sweden
| | - Lars Samuelson
- Division of Solid State Physics and NanoLund , Lund University , Box 118, 22100 Lund , Sweden
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8
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Høiaas IM, Liudi Mulyo A, Vullum PE, Kim DC, Ahtapodov L, Fimland BO, Kishino K, Weman H. GaN/AlGaN Nanocolumn Ultraviolet Light-Emitting Diode Using Double-Layer Graphene as Substrate and Transparent Electrode. NANO LETTERS 2019; 19:1649-1658. [PMID: 30702300 DOI: 10.1021/acs.nanolett.8b04607] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The many outstanding properties of graphene have impressed and intrigued scientists for the last few decades. Its transparency to light of all wavelengths combined with a low sheet resistance makes it a promising electrode material for novel optoelectronics. So far, no one has utilized graphene as both the substrate and transparent electrode of a functional optoelectronic device. Here, we demonstrate the use of double-layer graphene as a growth substrate and transparent conductive electrode for an ultraviolet light-emitting diode in a flip-chip configuration, where GaN/AlGaN nanocolumns are grown as the light-emitting structure using plasma-assisted molecular beam epitaxy. Although the sheet resistance is increased after nanocolumn growth compared with pristine double-layer graphene, our experiments show that the double-layer graphene functions adequately as an electrode. The GaN/AlGaN nanocolumns are found to exhibit a high crystal quality with no observable defects or stacking faults. Room-temperature electroluminescence measurements show a GaN related near bandgap emission peak at 365 nm and no defect-related yellow emission.
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Affiliation(s)
- Ida Marie Høiaas
- Department of Electronic Systems , Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim , Norway
| | - Andreas Liudi Mulyo
- Department of Electronic Systems , Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim , Norway
- Department of Engineering and Applied Sciences , Sophia University , 102-8554 Tokyo , Japan
| | | | - Dong-Chul Kim
- Department of Electronic Systems , Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim , Norway
| | - Lyubomir Ahtapodov
- Department of Electronic Systems , Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim , Norway
| | - Bjørn-Ove Fimland
- Department of Electronic Systems , Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim , Norway
| | - Katsumi Kishino
- Department of Engineering and Applied Sciences , Sophia University , 102-8554 Tokyo , Japan
- Sophia Nanotechnology Research Center , Sophia University , 102-8554 , Tokyo , Japan
| | - Helge Weman
- Department of Electronic Systems , Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim , Norway
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9
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Zhao C, Ebaid M, Zhang H, Priante D, Janjua B, Zhang D, Wei N, Alhamoud AA, Shakfa MK, Ng TK, Ooi BS. Quantified hole concentration in AlGaN nanowires for high-performance ultraviolet emitters. NANOSCALE 2018; 10:15980-15988. [PMID: 29897082 DOI: 10.1039/c8nr02615g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
p-Type doping in wide bandgap and new classes of ultra-wide bandgap materials has long been a scientific and engineering problem. The challenges arise from the large activation energy of dopants and high densities of dislocations in materials. We report here, a significantly enhanced p-type conduction using high-quality AlGaN nanowires. For the first time, the hole concentration in Mg-doped AlGaN nanowires is quantified. The incorporation of Mg into AlGaN was verified by correlation with photoluminescence and Raman measurements. The open-circuit potential measurements further confirmed the p-type conductivity, while Mott-Schottky experiments measured a hole concentration of 1.3 × 1019 cm-3. These results from photoelectrochemical measurements allow us to design prototype ultraviolet (UV) light-emitting diodes (LEDs) incorporating the AlGaN quantum-disks-in-nanowire and an optimized p-type AlGaN contact layer for UV-transparency. The ∼335 nm LEDs exhibited a low turn-on voltage of 5 V with a series resistance of 32 Ω, due to the efficient p-type doping of the AlGaN nanowires. The bias-dependent Raman measurements further revealed the negligible self-heating of devices. This study provides an attractive solution to evaluate the electrical properties of AlGaN, which is applicable to other wide bandgap nanostructures. Our results are expected to open doors to new applications for wide and ultra-wide bandgap materials.
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Affiliation(s)
- Chao Zhao
- King Abdullah University of Science and Technology (KAUST), Photonics Laboratory, Thuwal 23955-6900, Saudi Arabia.
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10
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Parida S, Das A, Prasad AK, Ghatak J, Dhara S. Native defect-assisted enhanced response to CH 4 near room temperature by Al 0.07Ga 0.93N nanowires. Phys Chem Chem Phys 2018; 20:18391-18399. [PMID: 29943784 DOI: 10.1039/c8cp02879f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Gas sensors at low operating temperature with high sensitivity require group III nitrides owing to their high chemical and thermal stabilities. For the first time, Al0.07Ga0.93N nanowires (NWs) have been utilized in CH4 sensing, and it has been demonstrated that they exhibit an improved response compared to GaN NWs at the low operating temperature of 50 °C. Al0.07Ga0.93N NWs have been synthesized via the ion beam mixing process using inert gas ion irradiation on the bilayer of Al/GaN NWs. The sensing mechanism is explained with the help of native defects present in the system. The number of shallow acceptors created by Ga vacancies (VGa) is found to be higher in Al0.07Ga0.93N NWs than in as-grown GaN NWs. The role of the O antisite defect (ON) for the formation of shallow VGa is inferred from photoluminescence spectroscopic analysis. These native defects strongly influence the gas sensing behaviour, which results in enhanced and low-temperature CH4 sensing.
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Affiliation(s)
- Santanu Parida
- Surface and Nanoscience Division, Indira Gandhi Centre for Atomic Research, Homi Bhabha National Institute, Kalpakkam-603102, India.
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11
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Liu X, Le BH, Woo SY, Zhao S, Pofelski A, Botton GA, Mi Z. Selective area epitaxy of AlGaN nanowire arrays across nearly the entire compositional range for deep ultraviolet photonics. OPTICS EXPRESS 2017; 25:30494-30502. [PMID: 29221077 DOI: 10.1364/oe.25.030494] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 11/12/2017] [Indexed: 06/07/2023]
Abstract
Semiconductor light sources operating in the ultraviolet (UV)-C band (100-280 nm) are in demand for a broad range of applications but suffer from extremely low efficiency. AlGaN nanowire photonic crystals promise to break the efficiency bottleneck of deep UV photonics. We report, for the first time, site-controlled epitaxy of AlGaN nanowire arrays with Al incorporation controllably varied across nearly the entire compositional range. It is also observed that an Al-rich AlGaN shell structure is spontaneously formed, significantly suppressing nonradiative surface recombination. An internal quantum efficiency up to 45% was measured at room-temperature. We have further demonstrated large area AlGaN nanowire LEDs operating in the UV-C band on sapphire substrate, which exhibit excellent optical and electrical performance, including a small turn-on voltage of ~4.4 V and an output power of ~0.93 W/cm2 at a current density of 252 A/cm2. The controlled synthesis of AlGaN subwavelength nanostructures with well-defined size, spacing, and spatial arrangement and tunable emission opens up new opportunities for developing high efficiency LEDs and lasers and promises to break the efficiency bottleneck of deep UV photonics.
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12
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13
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Sivadasan AK, Madapu KK, Dhara S. The light-matter interaction of a single semiconducting AlGaN nanowire and noble metal Au nanoparticles in the sub-diffraction limit. Phys Chem Chem Phys 2016; 18:23680-5. [PMID: 27511614 DOI: 10.1039/c6cp04681a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Near field scanning optical microscopy (NSOM) is not only a tool for imaging of sub-diffraction limited objects but also a prominent characteristic tool for understanding the intrinsic properties of nanostructures. In order to understand light-matter interactions in the near field regime using a NSOM technique with an excitation of 532 nm (2.33 eV), we selected an isolated single semiconducting AlGaN nanowire (NW) of diameter ∼120 nm grown via a vapor liquid solid (VLS) mechanism along with a metallic Au nanoparticle (NP) catalyst. The role of electronic transitions from different native defect related energy states of AlGaN is discussed in understanding the NSOM images for the semiconducting NW. The effect of strong surface plasmon resonance absorption of an excitation laser on the NSOM images for Au NPs, involved in the VLS growth mechanism of NWs, is also observed.
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Affiliation(s)
- A K Sivadasan
- Nanomaterials and Sensor Section, Surface and Nanoscience Division, Indira Gandhi Centre for Atomic Research, Homi Bhabha National Institute, Kalpakkam, 603102, Tamil Nadu, India.
| | - Kishore K Madapu
- Nanomaterials and Sensor Section, Surface and Nanoscience Division, Indira Gandhi Centre for Atomic Research, Homi Bhabha National Institute, Kalpakkam, 603102, Tamil Nadu, India.
| | - Sandip Dhara
- Nanomaterials and Sensor Section, Surface and Nanoscience Division, Indira Gandhi Centre for Atomic Research, Homi Bhabha National Institute, Kalpakkam, 603102, Tamil Nadu, India.
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14
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Belloeil M, Gayral B, Daudin B. Quantum Dot-Like Behavior of Compositional Fluctuations in AlGaN Nanowires. NANO LETTERS 2016; 16:960-966. [PMID: 26785291 DOI: 10.1021/acs.nanolett.5b03904] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report on the structural and optical properties of AlxGa(1-x)N nanowire sections grown by plasma-assisted molecular beam epitaxy on GaN nanowire bases used as a template. Based on a combination of scanning electron microscopy, microphotoluminescence, time-resolved microphotoluminescence, and photon correlation experiments, it is shown that compositional fluctuations in AlxGa(1-x)N sections associated with carrier localization optically behave as quantum dots. Moreover, most of the micro-optical properties of such fluctuations are demonstrated to be very little dependent on kinetic growth parameters such as AlxGa(1-x)N growth temperature and AlN molar fraction in the alloy, which govern the macrostructural properties of AlxGa(1-x)N sections.
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Affiliation(s)
- M Belloeil
- Univ. Grenoble Alpes , F-38000 Grenoble, France
- CEA, INAC-PHELIQS, "Nanophysics and Semiconductors" Group, F-38000 Grenoble, France
| | - B Gayral
- Univ. Grenoble Alpes , F-38000 Grenoble, France
- CEA, INAC-PHELIQS, "Nanophysics and Semiconductors" Group, F-38000 Grenoble, France
| | - B Daudin
- Univ. Grenoble Alpes , F-38000 Grenoble, France
- CEA, INAC-PHELIQS, "Nanophysics and Semiconductors" Group, F-38000 Grenoble, France
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Zhao S, Woo SY, Bugnet M, Liu X, Kang J, Botton GA, Mi Z. Three-Dimensional Quantum Confinement of Charge Carriers in Self-Organized AlGaN Nanowires: A Viable Route to Electrically Injected Deep Ultraviolet Lasers. NANO LETTERS 2015; 15:7801-7. [PMID: 26539880 DOI: 10.1021/acs.nanolett.5b02133] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We report on the molecular beam epitaxial growth and structural characterization of self-organized AlGaN nanowire arrays on Si substrate with high luminescence efficiency emission in the deep ultraviolet (UV) wavelength range. It is found that, with increasing Al concentration, atomic-scale compositional modulations can be realized, leading to three-dimensional quantum confinement of charge carriers. By further exploiting the Anderson localization of light, we have demonstrated, for the first time, electrically injected AlGaN lasers in the deep UV band operating at room temperature. The laser operates at ∼289 nm and exhibits a threshold of 300 A/cm(2), which is significantly smaller compared to the previously reported electrically injected AlGaN multiple quantum well lasers.
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Affiliation(s)
- S Zhao
- Department of Electrical and Computer Engineering, McGill University , 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - S Y Woo
- Department of Materials Science and Engineering, Canadian Centre for Electron Microscopy, McMaster University , 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
| | - M Bugnet
- Department of Materials Science and Engineering, Canadian Centre for Electron Microscopy, McMaster University , 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
| | - X Liu
- Department of Electrical and Computer Engineering, McGill University , 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - J Kang
- Department of Electrical and Computer Engineering, McGill University , 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - G A Botton
- Department of Materials Science and Engineering, Canadian Centre for Electron Microscopy, McMaster University , 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
| | - Z Mi
- Department of Electrical and Computer Engineering, McGill University , 3480 University Street, Montreal, Quebec H3A 0E9, Canada
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Lu H, Meng X. Correlation between band gap, dielectric constant, Young's modulus and melting temperature of GaN nanocrystals and their size and shape dependences. Sci Rep 2015; 5:16939. [PMID: 26582533 PMCID: PMC4652262 DOI: 10.1038/srep16939] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 10/22/2015] [Indexed: 11/23/2022] Open
Abstract
With structural miniaturization down to the nanoscale, the detectable parameters of materials no longer remain constant but become tunable. For GaN nanocrystals example, the band gap increases while the dielectric constant, Young’s modulus and melting temperature decrease with decreasing the solid size. Herein, we developed the models to describe the size and shape dependences of these seemingly uncorrelated parameters for GaN nanocrystals, based on our established thermodynamic model for cohesive energy of metallic nanocrystals. Consistency between our theoretical predictions and the corresponding experimental or simulated results confirms the accuracy of the developed models and indicates the essentiality of cohesive energy in describing the effects of size and shape on the physicochemical properties of different low-dimensional systems.
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Affiliation(s)
- Haiming Lu
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Institute of Materials Engineering, Nanjing University, Jiangsu 210093, People's Republic of China
| | - Xiangkang Meng
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Institute of Materials Engineering, Nanjing University, Jiangsu 210093, People's Republic of China
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Fath Allah R, Ben T, González D. Structural and chemical evolution of the spontaneous core-shell structures of AlxGa1-xN/GaN nanowires. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2014; 20:1254-1261. [PMID: 24698205 DOI: 10.1017/s1431927614000634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A study by electron microscopy techniques of the structural and compositional properties of Al x Ga1-x N/GaN nanowire (NW) heterostructures on Si(111) is presented. Al x Ga1-x N depositions grown without catalyst by plasma-assisted molecular beam epitaxy were designed to form NWs in the range of 0.20<x<0.40 with different lengths and growth temperatures. The NWs exhibit a well-defined core-shell radial structure with a complex chemical distribution along and across the growth direction that finally affects the NW morphology. All the wires have an initial stage with a maximum Al content in the core slightly above the GaN/Al x Ga1-x N interface, which initially decreases exponentially with the NW height depending on the nominal Al content and the growth temperature. In longer NWs, this trend changes and evolves increasing both the Al/Ga ratio and the core diameter as well as sharpening the shell. Adatom surface kinetic differences and the geometrical shadow effect during the growth are the probable drivers of this behavior.
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Affiliation(s)
- Rabie Fath Allah
- Dpto. Ciencia de los Materiales e Ingeniería Metalúrgica y Q.I.,Facultad de Ciencias,Apdo. 40,11510 Puerto Real,Cádiz,Spain
| | - Teresa Ben
- Dpto. Ciencia de los Materiales e Ingeniería Metalúrgica y Q.I.,Facultad de Ciencias,Apdo. 40,11510 Puerto Real,Cádiz,Spain
| | - David González
- Dpto. Ciencia de los Materiales e Ingeniería Metalúrgica y Q.I.,Facultad de Ciencias,Apdo. 40,11510 Puerto Real,Cádiz,Spain
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