Quintuple layer Bi2Se3 thin films directly grown on insulating SiO2 using molecular beam epitaxy

Topological insulator thin films on insulating SiO2 can be used in gate tunable devices, and have been prepared using exfoliation methods, but rarely with direct-growth methods. Here, we present our study to directly grow quintuple layer Bi2Se3 on insulating SiO2 using molecular beam epitaxy. We investigated atomic structures, stoichiometry, vibration modes, and surface morphology of the grown films using X-ray diffraction, Raman spectroscopy, and scanning tunneling microscopy, confirming that the grown films were Bi2Se3 quintuple layers. We then fabricated gate tunable devices using the films. Our study shows that Bi2Se3 can be directly prepared on non-crystalline insulator SiO2.