Effect of thermal annealing on the optical and structural properties of γ-Al2O3 films prepared on MgO substrates by MOCVD
| Autor: | Xianjin Feng, Jin Ma, Mingxian Wang, Xuejian Du, Weiguang Wang, Zhao Li |
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| Rok vydání: | 2016 |
| Předmět: |
010302 applied physics
Materials science Band gap Annealing (metallurgy) Process Chemistry and Technology 02 engineering and technology Chemical vapor deposition 021001 nanoscience & nanotechnology Epitaxy Microstructure 01 natural sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials Crystallography Transmission electron microscopy 0103 physical sciences Materials Chemistry Ceramics and Composites Metalorganic vapour phase epitaxy 0210 nano-technology High-resolution transmission electron microscopy |
| Zdroj: | Ceramics International. 42:551-558 |
| ISSN: | 0272-8842 |
| Popis: | Metalorganic chemical vapor deposition (MOCVD) of γ-Al 2 O 3 films is performed on MgO (110) and (111) substrates by using trimethylaluminum and O 2 as the precursors. The effects of post-deposition annealing on the microstructure and epitaxial relationship of the films are investigated by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Schematic diagrams are proposed to illuminate the epitaxial relationships between the γ-Al 2 O 3 films and MgO substrates. The γ-Al 2 O 3 films annealed at 1000 °C exhibit the best crystalline quality, for which clear epitaxial relationships of γ-Al 2 O 3 (110)∥MgO (110) with γ-Al 2 O 3 [ 1 ¯ 10 ] ∥MgO [ 1 ¯ 10 ] and γ-Al 2 O 3 (111)∥MgO (111) with γ-Al 2 O 3 [ 1 1 ¯ 0 ] ∥MgO [ 1 1 ¯ 0 ] have been ascertained. The average transmittance of the obtained samples in the visible range is over 85%. The optical band gaps of the γ-Al 2 O 3 films annealed at 1000 °C on MgO (110) and (111) substrates are about 5.81 and 5.80 eV, respectively, which are a bit smaller than those of the as-deposited films. |
| Databáze: | OpenAIRE |
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