Near-infrared photodetector based on Schottky junctions of monolayer graphene/GeOI

The peculiar properties of the large absorption coefficient at near-infrared frequencies as well as their high mobility in germanium enable promising applications in photodetection. Schottky junctions based near-infrared photodetectors were fabricated by integrating monolayer graphene film with germanium membranes stacking on silicon oxide substrates (i.e., GeOI). The device exhibits a strong photovoltaic behavior, giving rise to high responsivity and detectivity of ∼62.1 mA W−1 and ∼2.1 × 1011 cm Hz1/2 W−1, respectively. Time-response results indicate that the device could operate with the frequency up to 1 kHz. Our work may pave the way for exploiting graphene/GeOI Schottky junctions as the high-performance optoelectronic devices.