Enhancement of Photoresponsivity of β-In₂S₃/Si Broadband Photodetector by Decorating With Reduced-Graphene Oxide

Silicon-based conventional photodetectors have always been a vital part of many electronic and optoelectronic circuits because of their low fabrication cost, high device performance, and simple configuration. However, due to the relatively poor light–matter interaction and narrow bandgap in Si, these photodetectors generally suffer from a certain compromise in their photoresponsivity as well as broadband photoresponse. Here, a novel approach of coupling reduced-graphene oxide (rGO) decorated $\beta $ -In ₂ S ₃ with Si has been demonstrated. $\beta $ -In ₂ S ₃ thin film has been grown by a direct and transfer-free method on Si substrate and rGO has been drop-casted on $\beta $ -In ₂ S ₃ . This introduction of a double-heterojunction architecture results in a photoresponsivity of ~30.41 A/W at 625 nm at an applied voltage of −4 V with the response and recovery times of 60 and $40 ~\mu \text{s}$ , respectively, along with a broadband response in the wavelength range of 400–1200 nm. The rGO acts as an efficient hole transporting layer, which readily reduces the recombination of the photogenerated electrons and holes, leading to high photoresponse. These results highlight a simple and cost-effective strategy to construct high-performance broadband photodetectors, which can be useful in future optoelectronic devices.