Structural Characteristics and Photoluminescence Properties of Sputter-Deposition ZnGa₂O₄ Thin Films on Sapphire and Si(100) Substrates

• Main Authors: Wei-Kai Wang, Yi-Jie Xu, Shih-Yung Huang, Kuo-Feng Liu, Pi-Chuen Tsai
• Format: Article
• Language: English
• Published: MDPI AG 2019-07-01
• Series: Coatings
• Subjects: film; magnetron sputtering; microstructure
• Online Access: https://www.mdpi.com/2079-6412/9/8/469
• ISSN: 2079-6412

In this paper, we report the growth and material characteristics of ZnGa₂O₄ thin films on <i>c</i>-plane sapphire and Si(100) substrates by a radio-frequency magnetron sputtering. When deposited on sapphire, the ZnGa₂O₄ film showed a polycrystalline nature and a less randomly oriented, primarily with the (111), (222) and (511) planes parallel to the substrate surface. On Si(100), the ZnGa₂O₄ thin film was randomly oriented with (311)- and (020)-plane polycrystalline properties. Transmission electron microscopy analysis revealed that an amorphous-layer interface was formed on the Si(100) substrate and the microstructure of ZnGa₂O₄ became disordered. The ZnGa₂O₄/sapphire emitted ultraviolet photoluminescence and green emissions. The dominant optical transitions depended on the deposition temperature, oxygen and Zn contents, and nature of the substrate. The structural and optical properties of sputter-deposited ZnGa₂O₄ thin film on sapphire indicated that sapphire substrate is suitable for the growth of crystalline, high-quality ZnGa₂O₄ thin film.