2D InSe Self-Powered Schottky Photodetector with the Same Metal in Asymmetric Contacts

Self-powered photodetectors (SPPDs) are generally carried out in multilayered heterostructures with different semiconductors or in Schottky junctions with different metal electrodes. It is interesting to build an SPPD using metal-semiconductor-metal (MSM) structures with the same type of metal electrodes. Here, an SPPD is fabricated facilely by stacking a piece of irregular InSe nanosheet on a pair of Au electrodes with asymmetric van der Waals contacts. The SPPD performs a high responsivity of 0.103 A W-1, a high on-off current ratio over 10(4), a high detectivity of 1.83 x 10(10) Jones, a fast response time of 1 ms and a broadband sensing spectrum ranging from 300 to 1000 nm under zero bias. A series of characterization and working mechanism analysis demonstrate the contribution of the asymmetric Schottky barrier heights and contact geometries in Au-InSe junctions to the self-powered performance of the detector. This work offers an effective scheme to construct high-performance SPPDs in simple architecture and processing for potential optoelectronic device applications.

Automated summary

This study presents a method to fabricate self-powered photodetectors (SPPDs) using metal-semiconductor-metal (MSM) structures. A high-performance SPPD is achieved by stacking irregular InSe nanosheets on metal electrodes, resulting in high responsivity, high on-off current ratio, high detectivity, fast response time, and broadband sensing spectrum. The results demonstrate the importance of asymmetric Schottky barrier heights and contact geometries in Au-InSe junctions for the self-powered performance of SPPDs, offering an effective scheme for constructing high-performance SPPDs with simple architecture and processing.