Topological insulator Bi2Se3 thin films grown on double-layer graphene by molecular beam epitaxy

TL;DR

This study demonstrates the successful growth of high-quality, atomically flat Bi2Se3 topological insulator thin films on double-layer graphene using molecular beam epitaxy, with detailed characterization of growth conditions and electronic properties.

Contribution

First demonstration of epitaxial Bi2Se3 thin films on double-layer graphene with controlled growth conditions and low defect density.

Findings

Films exhibit low defect density (~1.0x10^11/cm^2)

Films become bulk insulators at 10 quintuple layers

Layer-by-layer growth achieved under specific Se-rich conditions

Abstract

Atomically flat thin films of topological insulator Bi2Se3 have been grown on double-layer graphene formed on 6H-SiC(0001) substrate by molecular beam epitaxy. By a combined study of reflection high energy electron diffraction and scanning tunneling microscopy, we identified the Se-rich condition and temperature criterion for layer-by-layer growth of epitaxial Bi2Se3 films. The as-grown films without doping exhibit a low defect density of 1.0\pm 0.2x1011/cm2, and become a bulk insulator at a thickness of 10 quintuple layers, as revealed by in situ angle resolved photoemission spectroscopy measurement.