RGO-Si QDs hybrid photodetector with enhanced photosensitivity

Abstract

This study presents a hybrid metal-insulator-semiconductor (MIS) photodetector integrating silicon quantum dots (Si QDs) with a multilayer reduced graphene oxide (rGO) film. A 1 nm amorphous silicon-on-insulator (SOI) film, deposited by molecular beam epitaxy (MBE), undergoes solid-state dewetting to form single-crystal Si QDs (∼6 nm) encapsulated in SiO₂. A multilayer graphene film is then deposited via spray coating, oxidized, and chemically reduced to obtain rGO, as confirmed by Raman analysis. The hybrid MIS structure, with transparent AuPd contacts, is characterized by capacitance-voltage (C-V) and current-voltage (I-V) measurements. The rGO enhances optoelectronic performance by improving charge collection and interaction with Si QDs. Experimental results demonstrate ultra-low dark current and a photocurrent amplified up to 100 times under low bias, highlighting the synergy between Si QDs' optical properties and rGO's efficient charge transport and open new pathways for the development of high-sensitivity, low-power optoelectronic devices.