Achieving Surface Quantum Oscillations in Topological Insulator Thin Films of Bi2Se3

High-quality thin films of topological insulator Bi2Se3 grown on sapphire substrates present a long phase coherence length and allow direct observations of surface quantum oscillations. The key to achieving high mobility of surface electrons is to raise the main deposition temperature to 300−320 °C, which necessitates a two-step deposition procedure with the initial epilayer deposited at 110−130 °C.