Different responses between undoped and N-doped few-layer graphene based photonic devices

In this paper, undoped and N-doped few-layer graphene (FLG) films were synthesized by ambient pressure chemical vapor deposition. The different photoresponse between these two kinds of FLG based photonic devices was discussed. Photoconductive and photovoltaic responses were found respectively in undoped and N-doped FLG based photonic devices. Under IR lamp illumination in vacuum, the resistance changed in undoped FLG based device while photocurrent at zero voltage bias was found in N-doped FLG based device. The photoconductive effect was enhanced as the temperature decreased, on the contrary, the photocurrent was found to decrease as the temperature decreased from room temperature to 78K.