Van der Waals epitaxy of Bi2Se3 on Si(111) vicinal surface: An approach to prepare high-quality thin films of topological insulator

TL;DR

This study demonstrates a van der Waals epitaxy method for growing high-quality Bi2Se3 topological insulator thin films on vicinal Si(111) substrates, achieving improved crystallinity and electronic properties.

Contribution

It introduces a two-step growth process and substrate orientation optimization to produce superior Bi2Se3 thin films with high mobility and reduced defects.

Findings

Carrier mobility of ~2000 cm2V-1s-1 achieved

Suppression of threading defects and twins

High magnetoresistance with linear magnetic field dependence

Abstract

Epitaxial growth of topological insulator Bi2Se3 thin films on nominally flat and vicinal Si(111) substrates is studied. In order to achieve planner growth front and better quality epifilms, a two-step growth method is adopted for the van der Waal epitaxy of Bi2Se3 to proceed. By employing vicinal Si(111) substrate surfaces, the in-pane growth rate anisotropy of Bi2Se3 is explored to achieve single crystalline Bi2Se3 epifilms, in which threading defects and twins are effectively suppressed. Optimization of the growth parameters has resulted in vicinal Bi2Se3 films showing a carrier mobility of ~ 2000 cm2V-1s-1 and the background doping of ~ 3 x 1018 cm-3 of the as-grown layers. Such samples not only show relatively high magnetoresistance but also a linear dependence on magnetic field.