Hot-carrier convection in graphene Schottky junctions

The exposed nature of the 2D electronic states in van der Waals materials are expected to render vertical transport in heterostructures highly susceptible to interfaces. We show that a new channel for energy transport - hot carrier convection - can be engineered in graphene Schottky junctions/interfaces. In this channel, hot carriers are vertically extracted through thermionic emission of graphene hot carriers into a semiconductor, thereby cooling the graphene electronic system. Large hot carrier convective energy currents can overwhelm conventional diffusive electronic energy transport, as well as dominate over electron-lattice cooling. Crucially, hot carrier convection features strongly coupled energy and charge currents that run vertically out of the graphene plane. This yields clear experimental signatures such as large and tunable responsivities of graphene Schottky junction photodetectors with a non-monotonic temperature dependence, opening up new approaches for engineering energy transport in 2D heterostructures.