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 × 104 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.