High-Performance Broadband Photodetection Enabled by a GeP/MoS₂ Van der Waals p-n Heterostructure

Abstract

Van der Waals (vdW) heterostructures based on two-dimensional (2D) semiconducting materials have been thoroughly investigated regarding practical applications. Recent studies on 2D materials have reignited attraction in the p-n junction, with promising potential for applications in both electronics and optoelectronics. Here, we presented a photodiode using a p-type GeP/n-type MoS 2 heterostructure with strong diode rectification of 2.1×10 4 , which proves the creation of a highquality p-n junction. The device has a high responsivity of about 752 AW -1 , high external quantum efficiency (EQE) of about 5.35×10 4 and a specific detectivity of about 4.25×10 12 Jones at a bias of 1V along source-drain. Photocurrent mapping shows the intrinsic photovoltaic behaviour with a photocurrent of 0.39 uA at zero bias condition which is enhanced to 0.60 uA at reverse bias condition and suppressed at forward bias condition which provides evidence of junctiondominated carrier separation. The measured photoresponse is sub-linear within a power-law with an exponent α = 0.65, and a stable response of the device with a rise and decay time of 165 millisecond and 206 milliseconds is achieved respectively. These results point to the GeP/MoS 2 vdW heterostructure as a potential platform for high-performance visible light photodetectors with a possibility to extend into the near-infrared region.