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Wei W, Yang Y, Peng Y, Maraj M, Sun W. Optical and Electrical Properties of Al xGa 1-xN/GaN Epilayers Modulated by Aluminum Content. Molecules 2024; 29:1152. [PMID: 38474664 DOI: 10.3390/molecules29051152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/22/2023] [Accepted: 01/04/2024] [Indexed: 03/14/2024] Open
Abstract
AlGaN-based LEDs are promising for many applications in deep ultraviolet fields, especially for water-purification projects, air sterilization, fluorescence sensing, etc. However, in order to realize these potentials, it is critical to understand the factors that influence the optical and electrical properties of the device. In this work, AlxGa1-xN (x = 0.24, 0.34, 0.47) epilayers grown on c-plane patterned sapphire substrate with GaN template by the metal organic chemical vapor deposition (MOCVD). It is demonstrated that the increase of the aluminum content leads to the deterioration of the surface morphology and crystal quality of the AlGaN epitaxial layer. The dislocation densities of AlxGa1-xN epilayers were determined from symmetric and asymmetric planes of the ω-scan rocking curve and the minimum value is 1.01 × 109 cm-2. The (101¯5) plane reciprocal space mapping was employed to measure the in-plane strain of the AlxGa1-xN layers grown on GaN. The surface barrier heights of the AlxGa1-xN samples derived from XPS are 1.57, 1.65, and 1.75 eV, respectively. The results of the bandgap obtained by PL spectroscopy are in good accordance with those of XRD. The Hall mobility and sheet electron concentration of the samples are successfully determined by preparing simple indium sphere electrodes.
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Affiliation(s)
- Wenwang Wei
- Research Center for Optoelectronic Materials and Devices, School of Physical Science & Technology, Guangxi University, Nanning 530004, China
- Guangxi Key Laboratory of Calcium Carbonate Resources Comprehensive Utilization, College of Materials and Chemical Engineering, Hezhou University, Hezhou 542899, China
| | - Yanlian Yang
- Research Center for Optoelectronic Materials and Devices, School of Physical Science & Technology, Guangxi University, Nanning 530004, China
| | - Yi Peng
- Research Center for Optoelectronic Materials and Devices, School of Physical Science & Technology, Guangxi University, Nanning 530004, China
| | - Mudassar Maraj
- Research Center for Optoelectronic Materials and Devices, School of Physical Science & Technology, Guangxi University, Nanning 530004, China
| | - Wenhong Sun
- Research Center for Optoelectronic Materials and Devices, School of Physical Science & Technology, Guangxi University, Nanning 530004, China
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Spasevski L, Buse B, Edwards PR, Hunter DA, Enslin J, Foronda HM, Wernicke T, Mehnke F, Parbrook PJ, Kneissl M, Martin RW. Quantification of Trace-Level Silicon Doping in Al x Ga 1-xN Films Using Wavelength-Dispersive X-Ray Microanalysis. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2021; 27:696-704. [PMID: 34218838 DOI: 10.1017/s1431927621000568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Wavelength-dispersive X-ray (WDX) spectroscopy was used to measure silicon atom concentrations in the range 35-100 ppm [corresponding to (3-9) × 1018 cm-3] in doped AlxGa1-xN films using an electron probe microanalyser also equipped with a cathodoluminescence (CL) spectrometer. Doping with Si is the usual way to produce the n-type conducting layers that are critical in GaN- and AlxGa1-xN-based devices such as LEDs and laser diodes. Previously, we have shown excellent agreement for Mg dopant concentrations in p-GaN measured by WDX with values from the more widely used technique of secondary ion mass spectrometry (SIMS). However, a discrepancy between these methods has been reported when quantifying the n-type dopant, silicon. We identify the cause of discrepancy as inherent sample contamination and propose a way to correct this using a calibration relation. This new approach, using a method combining data derived from SIMS measurements on both GaN and AlxGa1-xN samples, provides the means to measure the Si content in these samples with account taken of variations in the ZAF corrections. This method presents a cost-effective and time-saving way to measure the Si doping and can also benefit from simultaneously measuring other signals, such as CL and electron channeling contrast imaging.
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Affiliation(s)
- Lucia Spasevski
- Department of Physics, SUPA, University of Strathclyde, GlasgowG4 0NG, UK
| | - Ben Buse
- School of Earth Sciences, University of Bristol, BristolBS8 1RJ, UK
| | - Paul R Edwards
- Department of Physics, SUPA, University of Strathclyde, GlasgowG4 0NG, UK
| | - Daniel A Hunter
- Department of Physics, SUPA, University of Strathclyde, GlasgowG4 0NG, UK
| | - Johannes Enslin
- Institute of Solid State Physics, Technische Universität Berlin, BerlinD-10623, Germany
| | - Humberto M Foronda
- Institute of Solid State Physics, Technische Universität Berlin, BerlinD-10623, Germany
| | - Tim Wernicke
- Institute of Solid State Physics, Technische Universität Berlin, BerlinD-10623, Germany
| | - Frank Mehnke
- Institute of Solid State Physics, Technische Universität Berlin, BerlinD-10623, Germany
| | - Peter J Parbrook
- Tyndall National Institute, University College Cork, CorkT12 R5CP, Ireland
| | - Michael Kneissl
- Institute of Solid State Physics, Technische Universität Berlin, BerlinD-10623, Germany
- Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, BerlinD-12489, Germany
| | - Robert W Martin
- Department of Physics, SUPA, University of Strathclyde, GlasgowG4 0NG, UK
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