摘要
We reported a comparative study on the material–magnetotransport properties of topological insulator Bi2Se2Te and a ternary Bi3Se2Te-dominated thin films. The Bi-Se-Te thin films were grown on c-plane sapphire using pulsed laser deposition at various substrate temperatures (TS) of 180 – 300 °C. The highly c-axis-oriented films exhibited the Bi2Se2Te phase (at TS = 180, 220 °C), and a mixed phase of dominant Bi3Se2Te and mimor Bi2Se2Te (at TS = 260, 300 °C). In addition, XPS and EDS results confirmed the near stoichiometry compositions of Bi2Se2Te and Bi3Se2Te phases. In high magnetic fields, the magnetoresistance (MR) curves of Bi2Se2Te and Bi3Se2Te obeyed B2 power law, and the carrier mobility was determined to be increased monotonically from 61.3 to 86.9 cm2/Vs when TS increased from 180 to 300 °C. In low magnetic fields, MR curves of both Bi2Se2Te and Bi3Se2Te-dominated films presented two-dimensional weak antilocalization at low temperatures, possibly due to topological surface states in the thin films. Furthermore, we observed two acoustic phonon modes at 33.46 ± 0.69 GHz and 61.30 ± 1.75 GHz in both Bi2Se2Te and Bi3Se2Te-dominated thin films induced by ultrafast laser pulses.
原文 | English |
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文章編號 | 140241 |
期刊 | Thin Solid Films |
卷 | 791 |
DOIs | |
出版狀態 | Published - 29 2月 2024 |