Interfacial thermal transport of graphene/β-Ga2O3 heterojunctions: a molecular dynamics study with a self-consistent interatomic potential

Graphene/beta-Ga2O3 heterojunctions are widely used in high-power and high-frequency devices, for which thermal management is vital to the device operation and life. Here we apply molecular dynamics simulation to calculate the interfacial thermal resistance (ITR) between graphene and beta-Ga2O3. Based on the rigid ion model, a self-consistent interatomic potential with a set of parameters that can well reproduce the basic physical properties of crystal beta-Ga2O3 is fitted. Using this potential, the effects of model size, interface type, temperature, vacancy defects and graphene hydrogenation on the ITR of graphene/beta-Ga2O3 heterojunctions are evaluated. The results show that there is no obvious dependence of ITR on the size of graphene and beta-Ga2O3. It is reported that the ITR values of the (100), (010) and (001) interfaces are 7.28 +/- 0.35 x 10(-8) K m(2) W-1, 6.69 +/- 0.44 x 10(-8) K m(2) W-1 and 5.22 +/- 0.35 x 10(-8) K m(2) W-1 at 300 K, respectively. Both temperature increase and vacancy defect increase can prompt the energy propagation across graphene/beta-Ga2O3 interfaces due to the enhancement of phonon coupling. In addition, graphene hydrogenation provides new channels for in-plane and out-of-plane phonon coupling, and thus reduces the ITR between graphene and beta-Ga2O3. This study provides basic strategies for the thermal design and management of graphene/beta-Ga2O3 based photoelectric devices.