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Self‐Driven Metal–Semiconductor–Metal WSe 2 Photodetector with Asymmetric Contact Geometries
Author(s) -
Zhou Changjian,
Raju Salahuddin,
Li Bin,
Chan Mansun,
Chai Yang,
Yang Cary Y.
Publication year - 2018
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201802954
Subject(s) - photodetector , materials science , responsivity , optoelectronics , heterojunction , dark current , semiconductor , electrical contacts , doping
Self‐driven photodetectors have wide applications in wireless sensor networks and wearable physiological monitoring systems. While 2D materials have different bandgaps for potential novel application fields, the self‐driven photodetectors are mainly built on PN junctions or heterostructures, whose fabrication involves doping or reliable multiple transfer steps. In this study, a novel metal–semiconductor–metal (MSM) WSe 2 photodetector with asymmetric contact geometries is proposed. A high responsivity of 2.31 A W −1 is obtained under zero bias, and a large open‐circuit voltage of 0.42 V is achieved for an MSM photodetector with a large contact length difference. The MSM photodetector can overcome the disadvantage of high dark current in traditional MSM photodetectors. A small dark current of ≈1 fA along with a high detectivity of 9.16 × 10 11 Jones is achieved. The working principles and finite element analysis are presented to explain the origin of the self‐driven property and its dependence on the degree of asymmetry.