UC San Diego

Thermal transport in low dimensional materials play a critical role in the functionality and reliability of modern electronics. In 2D material based device, interface between 2D materials and substrates often limit the heat flow through the device. This thesis discusses the experimental measurements and theoretical modeling of thermal resistances at 2D material based device. First, we measure thermal conductivity and thermal resistance of bulk substrate by three-omega method. Next, we model the interfacial thermal resistance between the 2D material and substrates with the aid of phonon mismatch modelling. Finally, we quantify the total thermal resistance of a graphene based device by series resistance model. Our analysis shows majority of the resistance comes from the interfaces, and material’s intrinsic resistance becomes less significant at nanoscale. We find that the thermal resistance at the interface of graphene and substrate contributes to more than 50% of the total resistance. We attribute this high resistance at interface to weak Van der Waals interactions at the interface and dissimilar phonon vibrational properties of the materials. Our results suggest that increasing bond strength at the interface is an effective way to reduce the overall thermal resistance of the device. We compare our results with commonly used materials and interfaces, demonstrating the role of interface as potential application for heat guide or block in 2D material based device. This study will provide guide into the energy-efficient design and thermal management of 2D material devices.