Elastic properties of van der Waals epitaxy grown bismuth telluride 2D nanosheets

Abstract

Bismuth telluride (Bi₂Te₃) two-dimensional (2D) nanosheets prepared by van der Waals epitaxy were successfully detached, transferred, and suspended for nano-indentation measurements to be performed on freestanding circular nanosheets. The Young's modulus acquired by fitting linear elastic behaviors of 26 samples (thickness: 5–14 nm) is only 11.7–25.7 GPa, significantly smaller than the bulk in-plane Young's modulus (50–55 GPa). Compliant and robust Bi₂Te₃ 2D nanosheets suggest the feasibility of the elastic strain engineering of topological surface states.