Laser-induced photoresistance effect in Si-based vertical standing MoS2 nanoplate heterojunctions for self-powered high performance broadband photodetection

Abstract

MoS₂ has attracted extensive attention as the basic configuration of optoelectronic systems because of its outstanding optical and electronic properties. Although high performance MoS₂-based photodetectors have been realized by many groups, these studies are still in their initial stages of research, and more importantly, the usual photocurrent or photovoltage signals are fundamentally susceptible, thus seeking novel structures or working principle devices becomes more fascinating. Here, the MoS₂/Si heterojunction is prepared with a vertically standing nanoplate structure and we exploit it as a photovoltage, photocurrent and photoresistance-based multifunctional self-powered position sensitive detector (PSD). The PSD exhibits unprecedented performance with very high sensitivity (391.1 mV mm⁻¹, 285.2 μA mm⁻¹, and 21.61 KΩ mm⁻¹ for photovoltage, photocurrent and photoresistance responses, respectively), excellent linearity (nonlinearity <2%), and a very fast response speed (4.75 ms/6.33 ms), all of which are much better than those obtained in many other systems. More importantly, it is the first time that lateral photoresistance (LPRE) is observed in a MoS₂/Si heterojunction. Based on the theoretical analysis of the scattering or transportation modulation of photo-generated carriers on the drifted carriers in the MoS₂/Si heterojunction, these results are well explained.