The coherent heteroepitaxy of high-index Bi_2Se_3 thin film on nanofaceted Si(211) substrate

摘要

In this paper, high-index Bi2Se3(2045) films are achieved on a Bi-modified Si(211) substrate with corrugated surface morphologies composed of striplike 19.5 degrees tilted (001) facets by molecular beam epitaxy. The chemical bonds between Bi2Se3(001) faces and Bi-absorbed nanoscale faceted (111) terraces on Si(211) surfaces provide solid lattice constraints which favor the coherent epitaxy of Bi2Se3 films on the Bi-modified Si(211) substrate as compared to the H-passivated Si(211) substrate. This makes Bi2Se3(2045) grown on Bi-modified Si(211) more suitable for device applications. Temperature-dependent I-V measurements of the Bi2Se3(2045)/Si(211) heterojunction are performed which yield a Schottky barrier height of ?(B) = 0.22 eV at the heterointerface.