1205.5832 (Li Zhang et al.)

High Quality Ultrathin Bi2Se3 Films on CaF2 and CaF2/Si by MBE with a RF
Cracker Cell    [PDF]

Li Zhang, Robert Hammond, Merav Dolev, Min Liu, Alexander Palevski, Aharon Kapitulnik

We report a novel method to fabricate high quality Bi2Se3 thin films using MBE with a radio frequency cracker cell as an atomic selenium source. With rates close to exact stoichiometry, optimal layer-by-layer growth of high quality Bi2Se3 thin films, with smooth surfaces, has been achieved on CaF2(111) substrates and Si(111) substrates with a thin CaF2 buffer layer(CaF2/Si). Transport measurements on these films show a characteristic weak antilocalization mangnetoresistance, with emergence of weak localization in the ultrathin film limit. Quantum Oscillations attributed to the topological surface states have been observed, including in films on CaF2/Si.

View original: http://arxiv.org/abs/1205.5832