Photoconductivity of reduced graphene oxide and graphene oxide composite films

Abstract

A photoconductive device was fabricated by patterning magnetron sputtered Pt/Ti electrode and Reduced Graphene Oxide (RGO)/Graphene Oxide (GO) composite films with a sensitive area of 10×20mm2. The surface morphology of as-deposited GO films was observed by scanning electronic microscopy, optical microscopy and atomic force microscopy, respectively. The absorption properties and chemical structure of RGO/GO composite films were obtained using a spectrophotometer and an X-ray photoelectron spectroscopy. The photoconductive properties of the system were characterized under white light irradiation with varied output power and biased voltage. The results show that the resistance decreased from 210kΩ to 11.5kΩ as the irradiation power increased from 0.0008mW to 625mW. The calculated responsiveness of white light reached 0.53×10−3 A/W. Furthermore, the device presents a high photo-conductivity response and displays a photovoltaic response with an open circuit voltage from 0.017V to 0.014V with irradiation power. The sources of charge are attributed to efficient excitation dissociation at the interface of the RGO/GO composite film, coupled with cross-surface charge percolation.