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Gate-tunable photoresponse of defective graphene: from ultraviolet to visible.

Research paper by Kaliannan K Thiyagarajan, Balasubramaniam B Saravanakumar, Sang-Jae SJ Kim

Indexed on: 15 Jan '15Published on: 15 Jan '15Published in: ACS Applied Materials & Interfaces



Abstract

We report the gate-tunable photoresponse of a defective graphene over the ultraviolet (UV) and the visible light illumination, where the defect was generated by plasma irradiation. Plasma induced Dirac point shift indicates the p-doping effect. Interestingly the defective-graphene field effect transistor (defective-GFET) showed a negative shift upon UV illumination, whereas the device showed a positive shift under visible light illumination, along with the change in the photocurrent. The defective-GFET device showed a high photoresponsivity of 37 mA W(-1) under visible light, that is ∼3 times higher than that of the pristine graphene device. Photoinduced molecular desorption causes the UV light responsivity to 18 mA W(-1). This study shows that the tunable photodetector with high responsivity is feasible by introducing an artificial defect on graphene surface.