Comparative Study of Nanolayer ReS ₂ and ReS ₂ /Graphene vdW Heterostructure for High-Performance Photodetector Arrays

High-performance photodetectors are pivotal in applications such as optical communication, environmental monitoring, and biomedical sensing. Two-dimensional (2D) materials, particularly ReS2, have emerged as promising candidates for photodetectors due to their distinctive optical and electrical properties. In this work, a comparative study of the chemical vapor-deposited (CVD) and then transferred few-layer ReS2/monolayer graphene van der Waals (vdW) heterojunction photodetector and few-layer ReS2 photodetector in two 4 × 5 arrays has been reported. When the incident light has a wavelength of 405 nm with an optical power density of 5.04 mW/cm2 under bias conditions of Vgs = 0 V and Vds = 2 V, the ReS2/graphene heterostructure photodetector demonstrates significantly enhanced photoelectric performance, achieving a responsivity (R) of 42.15 A/W, a noise equivalent power (NEP) of 4.50 × 10–13 W/Hz1/2, an external quantum efficiency (EQE) of 1.29 × 104%, and a detectivity (D*) of 1.06 × 109 Jones. These performance metrics surpass those of the pure ReS2 photodetector, which exhibits corresponding values of 1.13 mA/W for R, 7.25 × 10–11 W/Hz1/2 for NEP, 0.35% for EQE, and 6.58 × 106 Jones for D*. Moreover, the heterojunction device shows a broader spectral response (from 365 to 940 nm). The superior performance of the heterojunction photodetector, evidenced by devices with extended channel widths, originates from the heterojunction’s role in promoting the separation of photogenerated carriers. Our findings provide an effective strategy for advancing the performance of 2D-material-based photodetectors for large-scale arrays.