Infrared photoelectric detection of polycrystalline Bi2Te3 thin films prepared by pulsed laser deposition

In the context of infrared photodetectors, the performances of infrared materials determine the photoresponse performance of devices. Bismuth telluride (Bi2Te3), as a topological insulator, is considered a strong competitor in the field of infrared photodetectors. In this study, polycrystalline Bi2Te3 thin films were prepared using pulsed laser deposition at different growth temperatures. The crystallization of Bi2Te3 films commenced at 150 °C, and with an increase in the preparation temperature, the crystal quality improved, reaching its peaks at 250 °C. Infrared performance of polycrystalline Bi2Te3 thin films were measured at low temperature, featuring a high responsivity of 56.98 mA/W and outstanding detectivity of 1.82 × 109 Jones, surpassing that of other two-dimensional materials. In a low-temperature environment, amorphous Bi2Te3 films are more prone to reaching photocurrent saturation compared to their crystalline counterparts. The generation of saturable photocurrent can be attributed to the effect of defect and disorder. Simultaneously, the presence of lattice defects enhances the photoresponse of the films. Essentially, these founding will pave the way to investigate of Bi2Te3 thin films for applications in infrared photodetectors.