Modeling of the separated thermal emission currents in graphene–semiconductor 2D/3D Schottky junctions

A new modeling theory of the separated emission currents in graphene–semiconductor Schottky junctions is reported in this work. Although some existing models modified by the Schottky diode equation can reproduce experimental data with a revised Richardson constant, the thermal emission current from graphene to a semiconductor cannot be calculated independently, and its physical meaning has not yet been well elucidated. In many previous models, the reverse current was simply defined using the thermal equilibrium condition. To fill this gap, we propose a new physics-based model that calculates the thermal emission currents across the 2D/3D junction based on the Landauer theory. This model has advantages compared with traditional methods. It calculates the two separated thermal emission current components independently and naturally satisfies the thermal equilibrium condition under the zero-bias condition. The non-ideal effects, including doping-enhanced barrier-lowering, are integrated into this model, leading to good agreement with experimental data. This model advances the understanding of the thermal emission current in graphene heterojunction electronic devices.