Ultrahigh-Sensitivity and Fast-Speed Solar-Blind Ultraviolet Photodetector Based on a Broken-Gap van der Waals Heterodiode
Li Zhang, Zhenhua Wei, Xiuxiu Wang, Luoyu Zhang, Yi Wang, Chao Xie, Tao Han, Feng Li, Wei Luo, Dongxu Zhao, Mingsheng Long, Lei Shan
Abstract
Broad-bandgap semiconductor-based solar-blind ultraviolet (SBUV) photodetectors have attracted considerable research interest because of their broad applications in missile plume tracking, flame detectors, environmental monitoring, and optical communications due to their solar-blind nature and high sensitivity with low background radiation. Owing to its high light absorption coefficient, abundance, and wide tunable bandgap of 2–2.6 eV, tin disulfide (SnS 2 ) has emerged as one of the most promising compounds for application in UV–visible optoelectronic devices. However, SnS 2 UV detectors have some undesirable properties such as slow response speed, high current noise level, and low specific detectivity. This study reports a metal mirror-enhanced Ta 0.01 W 0.99 Se 2 /SnS 2 (TWS) van der Waals heterodiode-based SBUV photodetector with an ultrahigh photoresponsivity ( R ) of ∼1.85 × 10 4 AW –1 and a fast speed with rising time (τ r ) of 3.3 μs and decay time (τ d ) of 3.4 μs. Notably, the TWS heterodiode device exhibits a significantly low noise equivalent power of ∼1.02 × 10 –18 W Hz –1/2 and a high specific detectivity of ∼3.65 × 10 14 cm Hz 1/2 W –1 . This study provides an alternative method for designing fast-speed SBUV photodetectors with enormous potential in applications.