In plane a & cross-plane thermoelectric characterizations of van der Waals heterostructures

In this work, I have studied thermoelectric transport across atomically abrupt interfaces. Thermoectric transport in heterostructures of thin film materials haven’t been studied thoroughly in literature because of lack of established tools and techniques for measurements. 2D materials, which are atomically thin provide an excellent platform to study thermoelectric transport across the interfaces. In this thesis I present a novel technique and device structure to study thermoelectric transport across Au/h-BN/graphene heterostructures. In addition to understanding mechanism of cross plane thermoelectric transport in heterostructures composed of 2D materials, I was also interested in understanding thermal transport in lateral direction when these materials are stacked on top of each other. More specifically, I was interested in graphene on BN as BN acts as a perfect substrate for graphene as most of the properties of graphene that gets subdued in silicon based substrate tend to recover when placed in graphene because of similar lattice structure of these two materials. In addition to thermoelectric transport, I also present my work in plasmonically enhanced photodiode based on graphene/insulator/graphene structure which can potentially be used for photocatalysis purposes. Lastly, I present my work in improving optoelectronic properties of GaAs nanowires using simple passivation technique—remote oxygen plasma treatment.