Enhanced UV-sensing properties by utilizing solution-processed GQD in GQDs/Porous Si heterojunction Near-UV photodetector

Abstract

This article evaluates the performance and photo-response of a GQDs (Graphene Quantum Dots)/Porous Si heterostructure near-UV sensor and compares it with the bare Porous Si device, indicating its effect on improving the sensor characteristics. The steps taken to fabricate each nanostructure and photosensor are explained. The morphology of each nanostructure is studied. The solution of GQDs is also examined by UV–Vis and FTIR spectroscopy. The photo-response of devices with and without GQD layers to near-ultraviolet light irradiation at 395 nm is investigated. With the inclusion of GQDs in the structure, the photocurrent and responsivity of the device are significantly improved. GQDs/Porous Si heterostructure UV photosensor demonstrates a responsivity of 19.41 A/W under a light power density of 21 μW/cm2 at room temperature, which is considerably increased compared to the absence of GQDs in the structure (0.49 A/W). The detectivity of 7.5 × 1012 Jones is reached, and the EQE (external quantum efficiency) stand at 6093%. The findings show the influential role of GQDs in the structure owing to their superior optical characteristics. The detection mechanism is also explained based on the band structure of the device.