Electronic structure and optical properties of Ge- and F-doped α-Ga2O3: First-principles investigationsProject supported by the National Natural Science Foundation of China (Grant No. 51302215) and the Natural Science Basic Research Program of Shaanxi Province, China (Grant Nos. 2018JQ6084 and 2019JQ-860)

• Published in: Chinese physics B 2020-12, Vol.29 (12)
• Main Authors: Shu, Ti-Kang, Miao, Rui-Xia, Guo, San-Dong, Wang, Shao-Qing, Zhao, Chen-He, Zhang, Xue-Lan
• Format: Article
• Language: English
• Subjects: calculation method; DFT; doping; Ga; GGA+
• ISSN: 1674-1056
• DOI: 10.1088/1674-1056/abbbff

The prospect of α-Ga2O3 in optical and electrical devices application is fascinating. In order to obtain better performance, Ge and F elements with similar electronegativity and atomic size are selected as dopants. Based on density functional theory (DFT), we systematically research the electronic structure and optical properties of doped α-Ga2O3 by GGA+U calculation method. The results show that Ge atoms and F atoms are effective n-type dopants. For Ge-doped α-Ga2O3, it is probably obtained under O-poor conditions. However, for F-doped α-Ga2O3, it is probably obtained under O-rich conditions. The doping system of F element is more stable due to the lower formation energy. In this investigation, it is found that two kinds of doping can reduce the α-Ga2O3 band gap and improve the conductivity. What is more, it is observed that the absorption edge after doping has a blue shift and causes certain absorption effect on the visible region. Through the whole scale of comparison, Ge doping is more suitable for the application of transmittance materials, yet F doping is more appropriate for the application of deep ultraviolet devices. We expect that our research can provide guidance and reference for preparation of α-Ga2O3 thin films and photoelectric devices.