Widely tunable band gap of the quantum-confined bismuth telluride nanocrystals

Abstract

Bismuth telluride is a famous material not only because of its excellent thermoelectric properties but also due to its unique topologically protected surface states. Here, based on first principle study, we theoretically calculated that the band gap of bismuth telluride (Eg = 0.16 eV) could be tuned to the visible and even ultraviolet region by approaching a nanoscale geometrical confinement in all three directions. This demonstration of widely tunable band gaps of bismuth telluride offers scope for developing this material into optoelectronics applications like light emitters and solar cells.