Effects of post-annealing on crystalline and transport properties of Bi2Te3 thin films* *Project supported by the National Natural Science Foundation of China (Grant Nos. 52072030, 52071025, and 51871018), the Beijing Outstanding Young Scientists Projects (Grant No. BJJWZYJH01201910005018), Beijing Natural Science Foundation, China (Grant No. Z180014), the Science and Technology Innovation Team Program of Foshan (Grant No. FSOAA-KJ919-4402-0087), and Beijing Laboratory

Abstract

A well-established method is highly desirable for growing topological insulator thin films with low carrier density on a wafer-level scale. Here, we present a simple, scalable method based on magnetron sputtering to obtain high-quality Bi2Te3 films with the carrier density down to 4.0 × 1013 cm−2. In contrast to the most-used method of high substrate temperature growth, we firstly sputtered Bi2Te3 thin films at room temperature and then applied post-annealing. It enables the growth of highly-oriented Bi2Te3 thin films with larger grain size and smoother interface. The results of electrical transport show that it has a lower carrier density as well as a larger coherent length (∼228 nm, 2 K). Our studies pave the way toward large-scale, cost-effective production of Bi2Te3 thin films to be integrated with other materials in wafer-level scale for electronic and spintronic applications.