Ultrasensitive photodetectors based on graphene quantum dot-InSe mixed-dimensional van der Waals heterostructures

Abstract

Two-dimensional (2D) semiconducting materials like InSe have attracted considerable attention in the photoelectric detection field due to their outstanding properties, such as a large tunable bandgap, high carrier mobility, low electron effective mass and high absorption coefficient. In this work, a mixed-dimensional van der Waals heterostructure (MvdWH)-based photodetector combining graphene quantum dots (GQDs) with InSe was fabricated. The GQD/InSe MvdWH photodetector achieved a high responsivity of 27.48 A W⁻¹ and a large detectivity of 1.2 × 10¹² Jones at 635 nm, a sixty-fold increase compared to the pure InSe devices. The significant enhancement in photoresponsive performances can be attributed to the p-type doping effect and efficient charge transfer from GQDs to InSe. The novel 0D/2D van der Waals heterojunctions offer tremendous opportunities in high-performance photodetectors.