Investigation of growth characteristics and semimetal–semiconductor transition of polycrystalline bismuth thin films
Nan Wang,
Yu-Xiang Dai,
Tian-Lin Wang,
Hua-Zhe Yang,
Yang Qi
Affiliations
Nan Wang
Department of Materials Physics and Chemistry, School of Materials Science and Engineering, State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, People's Republic of China
Yu-Xiang Dai
Department of Materials Physics and Chemistry, School of Materials Science and Engineering, State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, People's Republic of China
Tian-Lin Wang
Department of Materials Physics and Chemistry, School of Materials Science and Engineering, State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, People's Republic of China
Hua-Zhe Yang
Department of Biophysics, School of Fundamental Sciences, China Medical University, Shenyang, Liaoning 110122, People's Republic of China
Yang Qi
Department of Materials Physics and Chemistry, School of Materials Science and Engineering, State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, People's Republic of China
The preferred orientation growth characteristics and surface roughness of polycrystalline bismuth (Bi) thin films fabricated on glass substrates using the molecular beam epitaxy method were investigated at temperatures ranging from 18 to 150°C. The crystallization and morphology were analyzed in detail and the polycrystalline metal film structure-zone model (SZM) was modified to fit the polycrystalline Bi thin film. The boundary temperature between Zone T and Zone II in the SZM shifted to higher temperatures with the increase in film thickness or the decrease of growth rate. Furthermore, the effect of the thickness and surface roughness on the transport properties was investigated, especially for Bi thin films in Zone II. A two-transport channels model was adopted to reveal the influence of the film thickness on the competition between the metallic surface states and the semiconducting bulk states, which is consistent with the results of Bi single-crystal films. Therefore, the polycrystalline Bi thin films are expected to replace the single-crystal films in the application of spintronic devices.
