Interfacial charge transfer induced high photoresponsivity in WSe2/PdSe2 heterostructure photodetectors

Abstract

Two-dimensional (2D) materials exhibit significant potential for photodetection applications due to their superior light absorption properties and outstanding carrier mobility. The construction of heterojunctions by stacking distinct 2D materials enables optimization of interfacial charge transfer and broadband light absorption, thereby substantially enhancing the responsivity and detectivity of detectors. In this work, a high-performance WSe₂/PdSe₂ heterojunction photodetector was fabricated using chemical vapor deposition and micro-nano processing techniques. This device demonstrates a remarkable photoresponsivity of 42.47 A/W and a specific detectivity of 1.09 × 10¹² Jones under 532 nm laser irradiation. The built-in electric field at the heterojunction interface facilitates effective charge separation and transfer, resulting in improvements in detectivity and responsivity by one and two orders of magnitude, respectively, compared to devices based on individual WSe₂. These results underscore the pivotal potential of heterojunction engineering in advancing high-performance optoelectronic devices.