Van der Waals epitaxy of topological insulator Bi_2Se_3 on single layer transition metal dichalcogenide MoS_2

摘要

We report the growth of high quality topological insulator Bi_2Se_3 thin films on a single layer, transitional metal dichalcogenide MoS_2 film via van der Waals epitaxy in a planar geometry. In stark contrast to the reported growth of using 3-D crystalline substrates such as Al_2O_3(0001), Bi_2Se_3 thin films grown on a 2-D template made of single layer MoS_2 showed excellent crystallinity starting immediately from the growth of the first quintuple layer. Excellent crystallinity of Bi_2Se_3 thin films is attained, with the increased size of the triangular shaped Bi_2Se_3 domains and 2-3 times enhancement in mobility, along with the observation of Shubnikov-de Haas oscillations in the magnetoresistance. Our approach of adopting a van der Waals type template may be extended to the thin film growth of other low dimensional layered materials.