Photodetectors Based on Vertically Stacked Bi2Te3/WSe2 Heterojunctions for Visible to Near-Infrared Photodetection

Bismuth telluride (Bi2Te3) presents a promising option for producing high-performance semiconductor devices such as transistors and photodetectors thanks to its intriguing electrical properties as a topological insulator (TI). This study focuses on the precise nanoscale physical vapor deposition (PVD) growth of two-dimensional (2D) Bi2Te3 nanosheets and investigates their potential in high-performance photodetectors. In order to maximize the performance of Bi2Te3 nanosheet devices, we constructed a Bi2Te3/WSe2 heterojunction by a vertical stacking method, and the devices exhibited obvious current rectification behavior in the dark, effectively realizing the detection from visible light to near-infrared wavebands photodetection with excellent performance, including high responsivity (R = 7.6 A/W), the outstanding specific detectivity (D* = 3.01 × 1011 Jones), and fast response time (214/276 μs). The results of this work not only help to understand the PVD growth mechanism of Bi2Te3 nanosheets but also provide ideas for the construction of 2D Bi2Te3 nanostructured optoelectronic heterojunction devices.