Substrate preparation methods for improved synthesis of Bi₂Se₃ films grown on sapphire by molecular beam epitaxy

Bi₂Se₃ thin films have grown in popularity as three-dimensional topological insulators with a host of potential applications. While the films themselves have been widely researched, improvements derived from better substrate preparation have lagged. In this study, investigations into the preparation of c-plane sapphire (c-sapphire) substrates and the influence on film quality were done. Analysis on the effects of substrate pretreat by ultra-high vacuum annealing of the substrates, the use of Nano-strip® as an etchant, and high temperature in air anneal of c-sapphire to form a terraced morphology on Bi₂Se₃ thin film growth were done for this study.