Theory of photoexcited and thermionic emission across a two-dimensional graphene-semiconductor Schottky junction

摘要

We find that intrinsic graphene provides efficient photocarrier transportacross a two-dimensional graphene-semiconductor Schottky junction as a linearresponse to monochromatic light with excitation energy well below thesemiconductor bandgap. The operation mechanism relies both on zero-biasphotoexcited and thermionic emission contributing to photoresponsivity, enabledby the extended photocarrier thermalization time in intrinsic graphene. Thephotoresponsivity rapidly increases with excitation wavelength makinggraphene-semiconductor junctions attractive for photodetection at thetelecommunication frequency.