2D topological insulator bismuth selenide analyzed by in situ XPS

Abstract

Bismuth selenide (Bi2Se3), a two-dimensional topological insulator material purchased from Alfa Aesar, was analyzed using in situ x-ray photoelectron spectroscopy (XPS). The XPS spectra obtained from a fresh surface exfoliated in ultrahigh vacuum include a survey scan, high resolution spectra of O 1s, Bi 5d, Se 3d, Bi 4f, Se 3p, Se LMM, C 1s, and the valence band. Quantitative analysis indicates a Se deficient surface composition of Bi2Se2.8, which is consistent with the Fermi level position in the conduction band detected in this work.