Photocurrent enhancement of topological insulator by femtosecond laser controlled surface structure

Bismuth selenide (Bi₂Se₃) is a well-known topological insulator material with numerous applications in optoelectronics, spintronics, quantum computing, and other fields. In this study, large and uniform periodic surface structures were achieved in Bi₂Se₃ by a single scan with a linearly polarized femtosecond laser. The periodic surface structures can be precisely adjusted by changing the laser fluence and scanning speed. The simulation results of the absorption spectrum show that the obtained structure can effectively improve the optical absorption efficiency in the near-infrared band, which is conducive to further improving the photoelectric applications of the material. Furthermore, voltammetric tests demonstrate that the surface structure has significant advantages in increasing the current value of the topological optoelectronic device.