High-performance photodetector based on two-dimensional Sb₂Te₃/WS₂ vertical heterojunction

The layered Sb₂Te₃ material with a direct bandgap has significant potential for novel electronic and optoelectronic devices due to its advantages of being non-toxic, structurally stable, compositionally rich, with high carrier concentration and high carrier mobility. In this study, large-area monolayer WS₂ was first synthesized on SiO₂/Si substrates using chemical vapor deposition. The material was characterized by optical microscopy, scanning electron microscopy, atomic force microscopy, and Raman spectroscopy, and the experimental data confirmed the successful preparation of monolayer WS₂. Subsequently, a two-step chemical vapor deposition strategy was employed to selectively grow Sb₂Te₃ on the pre-synthesized WS₂/SiO₂/Si substrate, achieving the assembly of a p-Sb₂Te₃/n-WS₂ heterojunction. Finally, the two-dimensional p-Sb₂Te₃/n-WS₂ heterostructure was used in the fabrication of an optoelectronic detector, resulting in a fast response time with a rise time of 840 µs and a decay time of 1.52 ms. This research provides valuable insights into the construction of heterojunctions involving Sb₂Te₃ and other two-dimensional layered materials, contributing to the development of high-performance optoelectronic detectors.