Growth of Bi2Te3 topological insulator ultra-thin layers via molecular beam epitaxy on GaAs (100)

Abstract

Ultra-thin layers (<8 nm) of a Bi2Te3 topological insulator have been grown on GaAs (100) substrates using molecular beam epitaxy. The growth was performed from a single Bi2Te3 effusion cell and one source of extra tellurium. Optical and structural characterizations were carried out through Raman spectroscopy, x-ray diffraction, atomic force microscopy, and scanning electron microscopy. The topological insulator properties were also investigated by angle-resolved photoelectron spectroscopy. A layer of 5 nm showed Dirac cone-like linear electronic band dispersion, indicating the signature of a topological insulator with the Dirac point having large binding energy relative to the Fermi level as expected for ultra-thin films. Topological insulator properties were also investigated at the initial growth stage where deposition follows an islandlike growth mode. Our results can contribute to the development of practical chalcogenide-based thin-film spintronics devices.