High-performance broadband photodetection enabled by a GeP/MoS2 van der Waals p-n heterostructure

초록

van der Waals (vdW) heterostructures based on two-dimensional (2D) semiconducting materials have been thoroughly investigated for practical applications. Recent studies on 2D materials have reignited interest in p-n junctions, with promising potential for applications in both electronics and optoelectronics. Here, we present a photodiode using a p-type GeP/n-type MoS2 heterostructure with a strong diode rectification of 2.1 & times; 104, which confirms the creation of a high-quality p-n junction. The device has a high responsivity of about 754 A W-1 and a high external quantum efficiency (EQE) of about 5.35 & times; 104 at a bias of 1 V along the source-drain. Photocurrent mapping shows intrinsic photovoltaic behaviour with a photocurrent of 0.39 & micro;A under zero bias conditions, which is enhanced to 0.60 & micro;A under reverse bias conditions and suppressed under forward bias conditions, which provides evidence of junction-dominated carrier separation. The measured photoresponse is sub-linear within a power-law with an exponent alpha = 0.65, and a stable response of the device with a rise and decay time of 165 milliseconds and 206 milliseconds, respectively, is achieved. These results point to the GeP/MoS2 vdW heterostructure as a potential platform for high-performance visible light photodetectors with the possibility of extending into the near-infrared region.