Local photocurrent generation in thin films of the topological insulator Bi2Se3

摘要

We report on the optoelectronic properties of thin films of Bi₂Se₃ grown by molecular beam epitaxy. The films are patterned into circuits with typical extensions of tens of microns. In spatially resolved experiments, we observe submicron photocurrent patterns with positive and negative amplitudes. The patterns are independent of the applied bias voltage, but they depend on the width of the circuits. We interpret the patterns to originate from a local photocurrent generation due to potential fluctuations.