Heterostructured graphene quantum dot/WSe2/Si photodetector with suppressed dark current and improved detectivity
heterojunction, photodetector, Si, WSe2, graphene quantum dots
ABSTRACT A high-performance heterojunction photodetector is formed by combining an n-type Si substrate with p-type monolayer WSe2 obtained using physical vapor deposition. The high quality of the WSe2/Si heterojunction is demonstrated by the suppressed dark current of 1 nA and the extremely high rectification ratio of 107. Under illumination, the heterojunction exhibits a wide photoresponse range from ultraviolet to near-infrared radiation. The introduction of graphene quantum dots (GQDs) greatly elevates the photodetective capabilities of the heterojunction with strong light absorption and long carrier lifetimes. The GQDs/WSe2/Si heterojunction exhibits a high responsivity of ~ 707 mA·W–1, short response time of 0.2 ms, and good specific detectivity of ~ 4.51 × 109 Jones. These properties suggest that the GQDs/WSe2/Si heterojunction holds great potential for application in future high- performance photodetectors.
Tsinghua University Press
Mengxing Sun,Qiyi Fang,Dan Xie,Yilin Sun,Liu Qian,Jianlong Xu,Peng Xiao,Changjiu Teng,Weiwei Li,Tianling Ren,Yanfeng Zhang, Heterostructured graphene quantum dot/WSe2/Si photodetector with suppressed dark current and improved detectivity. NanoRes.2018, 11(6): 3233–3243