Impact of Temperature and Substrate Type on the Optical and Structural Properties of AlN Epilayers: A Cross-Sectional Analysis Using Advanced Characterization Techniques

AlN, with its ultra-wide bandgap, is highly attractive for modern applications in deep ultraviolet light-emitting diodes and electronic devices. In this study, the surface and cross-sectional properties of AlN films grown on flat and nano-patterned sapphire substrates are characterized by a variety...

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Main Authors: Wenwang Wei, Yi Peng, Yuefang Hu, Xiuning Xu, Quanwen Xie
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Molecules
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Online Access:https://www.mdpi.com/1420-3049/29/22/5249
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author Wenwang Wei
Yi Peng
Yuefang Hu
Xiuning Xu
Quanwen Xie
author_facet Wenwang Wei
Yi Peng
Yuefang Hu
Xiuning Xu
Quanwen Xie
author_sort Wenwang Wei
collection DOAJ
description AlN, with its ultra-wide bandgap, is highly attractive for modern applications in deep ultraviolet light-emitting diodes and electronic devices. In this study, the surface and cross-sectional properties of AlN films grown on flat and nano-patterned sapphire substrates are characterized by a variety of techniques, including photoluminescence spectroscopy, high-resolution X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and Raman spectroscopy. The results indicate that different sapphire substrates have minimal impact on the photoluminescence spectrum of the epitaxial films. As the temperature increased, the radius of curvature of the AlN films increased, while the warpage decreased. The AlN films grown on nano-patterned substrates exhibited superior quality with less surface oxidation. During the growth of AlN thin films on different types of substrates, slight shifts in the energy bands occurred due to differences in the introduction of carbon-related impurities and intrinsic defects. The Raman shift and full width at half maximum (FWHM) of the E<sub>2</sub>(low), A<sub>1</sub>(TO), E<sub>2</sub>(high), E<sub>1</sub>(TO), and E<sub>1</sub>(LO) phonon modes for the cross-sectional AlN films varied with the depth and temperature. The stress state within the film was precisely determined with specific depths and temperatures. The FWHM of the E<sub>2</sub>(high) phonon mode suggests that the films grown on nano-patterned substrates exhibited better crystalline quality.
format Article
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spelling doaj-art-784d23a5bb484a7f84a168b8efe851f62025-08-20T02:48:06ZengMDPI AGMolecules1420-30492024-11-012922524910.3390/molecules29225249Impact of Temperature and Substrate Type on the Optical and Structural Properties of AlN Epilayers: A Cross-Sectional Analysis Using Advanced Characterization TechniquesWenwang Wei0Yi Peng1Yuefang Hu2Xiuning Xu3Quanwen Xie4Guangxi Key Laboratory of Calcium Carbonate Resources Comprehensive Utilization, College of Materials and Chemical Engineering, Hezhou University, Hezhou 542899, ChinaCollege of Electric Power Engineering, Guangxi Vocational College of Water Resources and Electric Power, Nanning 530023, ChinaGuangxi Key Laboratory of Calcium Carbonate Resources Comprehensive Utilization, College of Materials and Chemical Engineering, Hezhou University, Hezhou 542899, ChinaGuangxi Key Laboratory of Calcium Carbonate Resources Comprehensive Utilization, College of Materials and Chemical Engineering, Hezhou University, Hezhou 542899, ChinaGuangxi Key Laboratory of Calcium Carbonate Resources Comprehensive Utilization, College of Materials and Chemical Engineering, Hezhou University, Hezhou 542899, ChinaAlN, with its ultra-wide bandgap, is highly attractive for modern applications in deep ultraviolet light-emitting diodes and electronic devices. In this study, the surface and cross-sectional properties of AlN films grown on flat and nano-patterned sapphire substrates are characterized by a variety of techniques, including photoluminescence spectroscopy, high-resolution X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and Raman spectroscopy. The results indicate that different sapphire substrates have minimal impact on the photoluminescence spectrum of the epitaxial films. As the temperature increased, the radius of curvature of the AlN films increased, while the warpage decreased. The AlN films grown on nano-patterned substrates exhibited superior quality with less surface oxidation. During the growth of AlN thin films on different types of substrates, slight shifts in the energy bands occurred due to differences in the introduction of carbon-related impurities and intrinsic defects. The Raman shift and full width at half maximum (FWHM) of the E<sub>2</sub>(low), A<sub>1</sub>(TO), E<sub>2</sub>(high), E<sub>1</sub>(TO), and E<sub>1</sub>(LO) phonon modes for the cross-sectional AlN films varied with the depth and temperature. The stress state within the film was precisely determined with specific depths and temperatures. The FWHM of the E<sub>2</sub>(high) phonon mode suggests that the films grown on nano-patterned substrates exhibited better crystalline quality.https://www.mdpi.com/1420-3049/29/22/5249AlNcross-sectional propertiestemperaturewarpageRaman spectra
spellingShingle Wenwang Wei
Yi Peng
Yuefang Hu
Xiuning Xu
Quanwen Xie
Impact of Temperature and Substrate Type on the Optical and Structural Properties of AlN Epilayers: A Cross-Sectional Analysis Using Advanced Characterization Techniques
Molecules
AlN
cross-sectional properties
temperature
warpage
Raman spectra
title Impact of Temperature and Substrate Type on the Optical and Structural Properties of AlN Epilayers: A Cross-Sectional Analysis Using Advanced Characterization Techniques
title_full Impact of Temperature and Substrate Type on the Optical and Structural Properties of AlN Epilayers: A Cross-Sectional Analysis Using Advanced Characterization Techniques
title_fullStr Impact of Temperature and Substrate Type on the Optical and Structural Properties of AlN Epilayers: A Cross-Sectional Analysis Using Advanced Characterization Techniques
title_full_unstemmed Impact of Temperature and Substrate Type on the Optical and Structural Properties of AlN Epilayers: A Cross-Sectional Analysis Using Advanced Characterization Techniques
title_short Impact of Temperature and Substrate Type on the Optical and Structural Properties of AlN Epilayers: A Cross-Sectional Analysis Using Advanced Characterization Techniques
title_sort impact of temperature and substrate type on the optical and structural properties of aln epilayers a cross sectional analysis using advanced characterization techniques
topic AlN
cross-sectional properties
temperature
warpage
Raman spectra
url https://www.mdpi.com/1420-3049/29/22/5249
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AT yuefanghu impactoftemperatureandsubstratetypeontheopticalandstructuralpropertiesofalnepilayersacrosssectionalanalysisusingadvancedcharacterizationtechniques
AT xiuningxu impactoftemperatureandsubstratetypeontheopticalandstructuralpropertiesofalnepilayersacrosssectionalanalysisusingadvancedcharacterizationtechniques
AT quanwenxie impactoftemperatureandsubstratetypeontheopticalandstructuralpropertiesofalnepilayersacrosssectionalanalysisusingadvancedcharacterizationtechniques