Self-powered photosensor based on curcumin:reduced graphene oxide (CU:rGO)/n-Si heterojunction in visible and UV regions

Abstract

This study proposes a novel photosensor that uses curcumin:reduced graphene oxide/silicon (CU:rGO)/ n -Si heterojunction, prepared at different molar ratios of rGO with CU. The CU:rGO was deposited on an n-Si by electrochemically. The EDX, XRD, SEM and absorbance analyses of CU:rGO film were investigated. From the I-V measurements, the all CU:rGO/ n -Si devices showed excellent rectification characteristics both in the dark and under various illumination intensities. The device with higher rGO ratio (labelled D1) had better performance overall having the rectification ratio of 86094, the ideality factor of 2.15 and photosensitivity of 198 (at 150 mW/cm 2 ), which was attributed to the extraordinary electro-optical properties of rGO. Hence, the electrical and optical properties of D1 device were analyzed in detailed. The typical I-V measurements were conducted both in dark and under AM 1.5 G illumination of various light intensities. The intensity of the incident light varied from 10 to 150 mW/cm 2 . The photocurrent exhibited a strong dependence on the light intensity. The I-V measurements of another device (labelled D4) prepared under the same conditions were achieved at 365 nm and 395 nm wavelengths and it showed good sensitivity to light even in the UV region. Furthermore, both D1 and D4 devices operated in self-powered mode in visible and UV light without the need for any external voltage. According to the experimental results, the produced CU:rGO/n-Si devices can be potential devices for photosensor applications in a wide spectral region. • A curcumin:reduced graphene oxide(CU:rGO/n-Si heterojunction photosensor, prepared at different molar ratios of rGO with CU. • The EDX, XRD, SEM and absorbance analyses of CU:rGO film were investigated. • The CU:rGO/ n -Si device showed excellent rectification characteristics both under visible and UV light illumination. • Both under visible light and at 365 nm and 395 nm, the device showed self-powered mode. • The photosensitivity reached to 1.0 × 10 5 at the zero biased point for 150 mW/cm 2 illumination power.