Multicolor Broadband and Fast Photodetector Based on InGaAs-Insulator-Graphene Hybrid Heterostructure

Broadband light detection is crucial for a variety of optoelectronic applications in modern society. As an important-near infrared (NIR) photodetector, InGaAs PIN photodiodes demonstrate high detection performance. However, they have a limited response range because of optical absorption by the window layer or substrate. To exploit the broadband absorption capability of narrow-bandgap InGaAs, a phototransistor based on a hybrid InGaAs-SiO2-graphene heterostructure is presented. In this system, graphene serves as a transparent conducting channel to sense optical absorption in the InGaAs. In contrast to InGaAs PIN photodiodes, the hybrid InGaAs phototransistor demonstrates multicolor photodetection over a broadband wavelength range from the ultraviolet to NIR. Furthermore, it manifests a high photoresponsivity of above 10(3) A W-1 under weak light irradiation, a large external quantum efficiency, and a fast response speed of 200 kHz. The results pave the way for the development of high-performance broadband photodetectors based on mixed-dimensional heterostructures.