In-situ spectroscopy of intrinsic Bi2Te3 topological insulator thin films and impact of extrinsic defects

TL;DR

This study uses in-situ spectroscopy techniques to analyze high-quality Bi2Te3 topological insulator thin films, demonstrating the preservation of surface states without bulk contribution and the stability of surface properties under certain conditions.

Contribution

It provides the first in-situ spectroscopic analysis of intrinsic Bi2Te3 thin films, showing they maintain topological surface states without bulk interference and are stable under in-vacuo storage.

Findings

High-quality stoichiometric Bi2Te3 films with topological surface states

Absence of bulk states at the Fermi energy without counter doping

Surface properties remain stable under in-vacuo storage and oxygen exposure

Abstract

Combined in-situ x-ray photoemission spectroscopy, scanning tunnelling spectroscopy and angle resolved photoemission spectroscopy of molecular beam epitaxy grown Bi2Te3 on lattice mismatched substrates reveal high quality stoichiometric thin films with topological surface states without a contribution from the bulk bands at the Fermi energy. The absence of bulk states at the Fermi energy is achieved without counter doping. We observe that the surface morphology and electronic band structure of Bi2Te3 are not affected by in-vacuo storage and exposure to oxygen, whereas major changes are observed when exposed to ambient conditions. These films help define a pathway towards intrinsic topological devices.