Graphene-on-silicon near-field thermophotovoltaic cell

Abstract

A graphene layer on top of a dielectric can dramatically influence ability of the material to radiative heat transfer. This property of graphene is used to improve the performance and reduce costs of near-field thermophotovoltaic cells. Instead of low bandgap semiconductors it is proposed to use graphene-on-silicon Schottky photovoltaic cells. One layer of graphene absorbs around 90% of incoming radiation and increases the heat transfer. This is due to excitation of plasmons in graphene, which are automatically tuned in resonance with the emitted light in the mid infrared range. The absorbed radiation excites electron-hole pairs in graphene, which are separated by the surface field induced by the Schottky barrier. For a quasi-monochromatic source the generated power is one order of magnitude larger and efficiency is on the same level as for semiconductor photovoltaic cells.Comment: 6 pages, 3 figures, to be published in Phys. Rev. Applie