Characteristic Features of 1/f Noise in Graphene Field-Effect Transistor Photodetectors

Graphene has been investigated intensely for optoelectronic applications, especially for field-effect transistor photodetectors. To evaluate the capability of weak light detection of a photodetector, the noise equivalent power can be estimated by characterizing the 1/f noise or flicker noise. Here, we experimentally demonstrate characteristic features of field-effect transistor photodetectors, which consist of a single graphene layer and a Ta2O5 dielectric thin film engineered by Atomic Layer Deposition method. The graphene field-effect mobility and low frequency 1/f noise are investigated in this study. Our devices show a low level of 1/f noise, with the spectral noise density of ~10-20 A2Hz-1 at 10 Hz, and a high carrier mobility of 6500 cm2/(V.s). The demonstrated graphene photodetector based on the field-effect transistor structure is important for the optoelectronic applications of graphene.