Local photocurrent generation in thin films of the topological insulator Bi2Se3

TL;DR

This paper investigates the optoelectronic properties of Bi2Se3 thin films, revealing local photocurrent patterns caused by potential fluctuations, which are independent of bias but depend on circuit width.

Contribution

It demonstrates the spatially resolved photocurrent patterns in Bi2Se3 thin films and attributes them to local potential fluctuations, advancing understanding of topological insulator optoelectronics.

Findings

Submicron photocurrent patterns observed

Patterns are independent of bias voltage

Photocurrent depends on circuit width

Abstract

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 amplitude. 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.