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 (<i>R</i> = 7.6 A/W), the outstanding specific detectivity (<i>D</i>* = 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.