title: Gate-tunable photoresponse of defective graphene: from ultraviolet to visible.
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.
authors.affiliation: Nanomaterials and System Lab, Department of Mechatronics Engineering, Jeju National University , Jeju 690-756, Republic of Korea.
authors.forename: Kaliannan
authors.initials: K
authors.lastname: Thiyagarajan
authors.forename: Balasubramaniam
authors.initials: B
authors.lastname: Saravanakumar
authors.forename: Sang-Jae
authors.initials: SJ
authors.lastname: Kim
keywords: defects; field effect transistors; graphene; photocurrent; plasma irradiation