Investigation and characterization of graphene for optical sensing

We report a strong electron-photon interaction in exfoliated graphene observed at room temperature. Graphene has great potential to optoelectronic applications because of its excellent optical properties. Here, we demonstrate using the graphene-based structure for infrared detection under a zero-bias operation. When infrared light is projected to graphene, the graphene is capable to generate photocurrents. Besides, the electron-hole pairs generation of the graphene-based structure is independent of the direction of the polarized infrared source, and this makes graphene suitable for optical sensing. The device structure consists of graphene contacted with a pair of metal electrodes, which were fabricated using two nanomanipulation processes: dielectrophoresis and atomic force microscopic based nano assembly.