Metal-semiconductor-metal photodetectors based on graphene/p-type silicon Schottky junctions

Metal-semiconductor-metal (MSM) photodetectors based on graphene/p-type Si Schottky junctions are fabricated and characterized. Thermionic emission dominates the transport across the junctions above 260 K with a zero-bias barrier height of 0.48 eV. The reverse-bias dependence of the barrier height is found to result mostly from the Fermi level shift in graphene. MSM photodetectors exhibit a responsivity of 0.11 A/W and a normalized photocurrent-to-dark current ratio of 4.55 x 10(4) mW(-1), which are larger than those previously obtained for similar detectors based on carbon nanotubes. These results are important for the integration of transparent, conductive graphene electrodes into existing silicon technologies. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4773992]