Self-powered waveguide-integrated photodetector based on a defect-engineered WSe2/graphene heterojunction

Abstract

With integration capability and excellent photoelectronic, two-dimensional materials have attracted increasing interest in photonic circuits as waveguide-integrated photodetectors. Here, we report a waveguide-integrated self-powered photodetector based on a defect-engineered WSe2/graphene (WSe2/G) heterostructure. The WSe2 side of the heterostructure is locally irradiated by the Ga+ ion beam generating S-vacancies (WSe2-0.18/G). The boundary of the irradiated and non-irradiated regions (WSe2/G-WS2-0.18/G) construct a Schottky-metal junction with the photovoltaic property. This WSe2/G-WS2-0.18/G heterostructure exhibits a broad spectral photoresponse from 450 nm to 1550 nm at 0 bias with on/off ratio of 104. As a self-powered photodetector, WSe2/G-WS2-0.18/G heterostructure is integrated with a polymer waveguide. It directly reads optical signal (100 kHz @ 1550 nm) in the waveguide. Our work paves a novel avenue to prepare the self-powered 2D photodetector for integration with photonic circuits.