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

Graphene/β-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 β-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 β-Ga2O3 is fitted. Using this potential, the effects of model size, interface type, temperature, vacancy defects and graphene hydrogenation on the ITR of graphene/β-Ga2O3 heterojunctions are evaluated. The results show that there is no obvious dependence of ITR on the size of graphene and β-Ga2O3. It is reported that the ITR values of the (100), (010) and (001) interfaces are 7.28 ± 0.35 × 10-8 K m2 W-1, 6.69 ± 0.44 × 10-8 K m2 W-1 and 5.22 ± 0.35 × 10-8 K m2 W-1 at 300 K, respectively. Both temperature increase and vacancy defect increase can prompt the energy propagation across graphene/β-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 β-Ga2O3. This study provides basic strategies for the thermal design and management of graphene/β-Ga2O3 based photoelectric devices.