Degenerate layer at ZnO/sapphire interface
Li, L; Shan, C X; Wang, S P; Li, B H; Zhang, J Y; Yao, B; Shen, D Z; Fan, X W; Lu, Y M; Li, L; Key Lab of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, People's Republic of China; Graduate School of The Chinese Academy of Sciences, Beijing, 100049, People's Republic of China; Shan, C X; Key Lab of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, People's Republic of China;; Wang, S P; Key Lab of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, People's Republic of China; Graduate School of The Chinese Academy of Sciences, Beijing, 100049, People's Republic of China; Li, B H; Key Lab of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, People's Republic of China; Zhang, J Y; Key Lab of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, People's Republic of China; Yao, B; Key Lab of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, People's Republic of China; Shen, D Z; Key Lab of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, People's Republic of China; Fan, X W; Key Lab of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, People's Republic of China; Lu, Y M; College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, People's Republic of China
Журнал:
Journal of Physics D: Applied Physics
Дата:
2009-10-07
Аннотация:
Zinc oxide (ZnO) films have been prepared on sapphire substrates by molecular beam epitaxy. It is found that the electron concentration of the films decreases, while the mobility increases with increasing the film thickness. Temperature-dependent Hall measurement reveals the existence of a degenerate layer at the ZnO/sapphire interface, which will increase the electron concentration and decrease the mobility in the ZnO film. By using a two-layer conduction model, the electron concentration and mobility of the film excluding the influence of the degenerate layer have been determined. A fitting to the corrected electron concentration of the ZnO film yields an activation energy of about 31 meV for the residual donors.
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