Efficient Photothermal and Photocurrent Enhancements in Bi₂Te₃ Topological Insulator Nanofilm by Integrating with a Photonic Crystal

Abstract Bismuth telluride (Bi 2 Te 3 ) topological insulator (TI) presents excellent photothermoelectric characteristics with promising applications in photonic detection, catalysis, and sensing. Exploring effective approaches to enhance the photothermal and photocurrent response in the Bi 2 Te 3 TI films is particularly significant for improving the photodetection capacity. Herein, the generation of an optical effect analogous to Tamm plasmons is experimentally and numerically demonstrated by integrating the Bi 2 Te 3 TI nanofilm onto a 1D photonic crystal (PC). The Bi 2 Te 3 /PC multilayer enables the distinct enhancement of near‐infrared light absorption and photothermal effect of Bi 2 Te 3 nanofilm based on the TI‐based optical Tamm state. The measured results reveal that the reflection spectrum of Bi 2 Te 3 nanofilm on the PC exhibits a distinct dip, whose position has a redshift with increasing the thickness of Bi 2 Te 3 film. The numerical and theoretical calculations agree well with the experiments. The reflection dip stems from the formation of the TI‐based Tamm state, whose wavelength exhibits a slight blueshift with the increase of temperature. The zero‐bias photocurrent conversion of Bi 2 Te 3 nanofilm can be obviously self‐reinforced with impinging light on the Bi 2 Te 3 /PC structure at the Tamm state wavelength. The results pave a new avenue for enhancing light‐TI interactions and their applications in high‐performance near‐infrared photodetection devices.