A Self‐Powered Photodetector Based on Graphene Enhanced WSe<sub>2</sub>/PtSe<sub>2</sub> Heterodiode with Fast Speed and Broadband Response
Xiuxiu Wang, Suofu Wang, Yanwei Wu, Wenhui Wang, Zhangyu Cao, Binbin Wei, Tao Han, Feng Li, Shaoliang Wang, Lei Shan, Mingsheng Long
Abstract
Abstract Narrow bandgap 2D layered material platinum selenide (PtSe 2 ) with good environmental stability, high carrier mobility, and high light absorption, has been widely investigated for uncooled midwave‐infrared (MWIR) photodetection. However, the phototransistor based on the PtSe 2 operation at room temperature suffered from the high dark current and background noise. Here, a graphene (G)‐enhanced G‐WSe 2 /PtSe 2 hetero‐diode placed on a metal electrode is reported. To enhance the photogain, a graphene layer placed on the WSe 2 /PtSe 2 heterodiode as a local gating layer is designed. The device exhibits an ultra‐high light on/off ratio of up to 10 8 and ultra‐fast photoresponse speed with raising time τ r = 0.9 µs and decay time of τ d = 1.5 µs in the visible spectra range. Notably, ultrabroad band photoresponse from 405 to 3366 nm is demonstrated under the self‐power model. Notably, the device presented a competitive photovoltaic effect with a high energy conversion efficiency (PCE) of 3.45%. The results pave the way toward a new approach to tuning the performance of the atomic thin layered materials photodetector.