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

Highlights: • Bi₂Se₃ thin film was prepared on non-crystalline SiO₂ substrate using molecular beam epitaxy. • The Bi₂Se₃ thin film properties were analyzed by X-ray diffraction, Raman spectroscopy, scanning tunneling microscopy and electronic transport measurement. - Abstract: 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