Growth, Morphology and Stability of Au in Contact with the Bi2Se3(0001) Surface

TL;DR

This study investigates how gold deposits on Bi2Se3(0001) surfaces, revealing island formation, stability issues upon heating, minimal impact on topological states, and chemical inertness towards CO and CO2 gases.

Contribution

It provides new insights into the growth, stability, and chemical properties of Au on Bi2Se3(0001), highlighting differences from other metals and the weak interaction with the surface state.

Findings

Au forms islands via Volmer-Weber growth mode

Au islands are unstable and coalesce upon annealing to 100°C

The topological surface state remains weakly affected by Au presence

Abstract

We report a combined microscopy and spectroscopy study of Au deposited on the Bi2Se3(0001) single crystal surface. At room temperature Au forms islands, according to the Volmer-Weber growth mode. Upon annealing to 100{\deg} C the Au deposits are not stable and assemble into larger and thicker islands. The topological surface state of Bi2Se3 is weakly affected by the presence of Au. Contrary to other metals, such as Ag or Cr, a strong chemical instability at the Au/Bi2Se3 interface is ruled out. Core level analysis highlights Bi diffusion toward the surface of Au islands, in agreement with previous findings, while chemical interaction between Au and atomic Se is limited at the interfacial region. For the investigated range of Au coverages, the Au/Bi2Se3 heterostructure is inert towards CO and CO2 exposure at low pressure (10-8 mbar) regime.