Photoconductivity in High-Quality Graphene

Graphene is a relatively new material with unique properties that found application in the field of electronics and optoelectronics. A broadband absorption makes it especially interesting for photodetection applications. Middle-infrared domain of electromagnetic spectrum still lacks active media for photodetection that are cheap, do not contain toxic elements and do not require additional cooling. This work is focused on the fabrication of a graphene-based photodetector for middle-infrared domain and on the photoresponsivity mechanisms in this region where direct absorption by graphene does not play the dominant role. Several steps to improve the device quality are considered and the photocurrent measurements in the middle-infrared are performed and analysed. The substrate properties such as dielectric permittivity dispersion of the silicon oxide and the hyperbolic nature of hexagonal Boron Nitride are found to introduce essential contribution to the photocurrent enhancement mechanism.