Mosaic Structure of GaN Film Grown on Sapphire Substrate by AP-MOCVD: Impact of Thermal Annealing on the Tilt and Twist Angles
A GaN layer with a thickness of 2 µm was grown on a sapphire substrate using atmospheric pressure metal–organic chemical vapor deposition (AP-MOCVD). Subsequently, the layer was annealed under a nitrogen atmosphere at temperatures ranging from 1000 °C to 1120 °C. High-resolution X-ray diffraction (H...
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| author | J. Laifi M. F. Hasaneen H. Bouazizi Fatimah Hafiz Alsahli T. A. Lafford A. Bchetnia |
| author_facet | J. Laifi M. F. Hasaneen H. Bouazizi Fatimah Hafiz Alsahli T. A. Lafford A. Bchetnia |
| author_sort | J. Laifi |
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| description | A GaN layer with a thickness of 2 µm was grown on a sapphire substrate using atmospheric pressure metal–organic chemical vapor deposition (AP-MOCVD). Subsequently, the layer was annealed under a nitrogen atmosphere at temperatures ranging from 1000 °C to 1120 °C. High-resolution X-ray diffraction (HRXRD) analysis reveals the impact of thermal annealing on the mosaic structure of the GaN, specifically the tilt and twist variations in four planes: (00.2), (10.3), (10.2), and (10.1). Interestingly, the observed trends suggest a differential effect of annealing on screw and edge dislocation densities. The annealing process reduces the edge and screw dislocation density. Lower values (<i>D<sub>screw</sub></i> = 1.2 × 10<sup>8</sup> cm<sup>−2</sup>; <i>D</i><sub>edge</sub> = 1.6 × 10<sup>9</sup> cm<sup>−2</sup>) were obtained for the sample annealed at 1050 °C. Notably, both tilt and twist angles exhibited a minimum at 1050 °C (tilt = 252 arcsecs, and twist = 558 arcsecs), indicating improved crystal quality at this specific temperature. Photoluminescence (PL) spectroscopy further complemented the structural analysis. The intensity and broadening of the yellow band (YL) in the PL spectra progressively increased with the increasing annealing temperature, suggesting the presence of additional defect states. The near band edge PL emission (3.35 and 3.41 eV) variation upon thermal annealing was correlated with the mosaic structure evolution. |
| format | Article |
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| spelling | doaj-art-64eb36e1b395420bb285410fe8b9fefd2025-01-24T13:28:18ZengMDPI AGCrystals2073-43522025-01-011519710.3390/cryst15010097Mosaic Structure of GaN Film Grown on Sapphire Substrate by AP-MOCVD: Impact of Thermal Annealing on the Tilt and Twist AnglesJ. Laifi0M. F. Hasaneen1H. Bouazizi2Fatimah Hafiz Alsahli3T. A. Lafford4A. Bchetnia5Physics Department, College of Science, Jouf University, Sakaka P.O. Box 2014, Saudi ArabiaPhysics Department, College of Science, Jouf University, Sakaka P.O. Box 2014, Saudi ArabiaFaculty of Sciences, Monastir University, Monastir 5060, TunisiaDepartment of Physics, College of Science, Qassim University, Qassim 86812, Saudi ArabiaBruker Corporation, Billerica, MA 01821, USADepartment of Physics, College of Science, Qassim University, Qassim 86812, Saudi ArabiaA GaN layer with a thickness of 2 µm was grown on a sapphire substrate using atmospheric pressure metal–organic chemical vapor deposition (AP-MOCVD). Subsequently, the layer was annealed under a nitrogen atmosphere at temperatures ranging from 1000 °C to 1120 °C. High-resolution X-ray diffraction (HRXRD) analysis reveals the impact of thermal annealing on the mosaic structure of the GaN, specifically the tilt and twist variations in four planes: (00.2), (10.3), (10.2), and (10.1). Interestingly, the observed trends suggest a differential effect of annealing on screw and edge dislocation densities. The annealing process reduces the edge and screw dislocation density. Lower values (<i>D<sub>screw</sub></i> = 1.2 × 10<sup>8</sup> cm<sup>−2</sup>; <i>D</i><sub>edge</sub> = 1.6 × 10<sup>9</sup> cm<sup>−2</sup>) were obtained for the sample annealed at 1050 °C. Notably, both tilt and twist angles exhibited a minimum at 1050 °C (tilt = 252 arcsecs, and twist = 558 arcsecs), indicating improved crystal quality at this specific temperature. Photoluminescence (PL) spectroscopy further complemented the structural analysis. The intensity and broadening of the yellow band (YL) in the PL spectra progressively increased with the increasing annealing temperature, suggesting the presence of additional defect states. The near band edge PL emission (3.35 and 3.41 eV) variation upon thermal annealing was correlated with the mosaic structure evolution.https://www.mdpi.com/2073-4352/15/1/97GaNcrystal structurex-ray diffractionthermal annealing |
| spellingShingle | J. Laifi M. F. Hasaneen H. Bouazizi Fatimah Hafiz Alsahli T. A. Lafford A. Bchetnia Mosaic Structure of GaN Film Grown on Sapphire Substrate by AP-MOCVD: Impact of Thermal Annealing on the Tilt and Twist Angles Crystals GaN crystal structure x-ray diffraction thermal annealing |
| title | Mosaic Structure of GaN Film Grown on Sapphire Substrate by AP-MOCVD: Impact of Thermal Annealing on the Tilt and Twist Angles |
| title_full | Mosaic Structure of GaN Film Grown on Sapphire Substrate by AP-MOCVD: Impact of Thermal Annealing on the Tilt and Twist Angles |
| title_fullStr | Mosaic Structure of GaN Film Grown on Sapphire Substrate by AP-MOCVD: Impact of Thermal Annealing on the Tilt and Twist Angles |
| title_full_unstemmed | Mosaic Structure of GaN Film Grown on Sapphire Substrate by AP-MOCVD: Impact of Thermal Annealing on the Tilt and Twist Angles |
| title_short | Mosaic Structure of GaN Film Grown on Sapphire Substrate by AP-MOCVD: Impact of Thermal Annealing on the Tilt and Twist Angles |
| title_sort | mosaic structure of gan film grown on sapphire substrate by ap mocvd impact of thermal annealing on the tilt and twist angles |
| topic | GaN crystal structure x-ray diffraction thermal annealing |
| url | https://www.mdpi.com/2073-4352/15/1/97 |
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