Thermal transport in enhanced thermoelectric performance high FOM Sb2Te3/MoS2 heterostructure

Agarwal, Khushboo and Gonzalez Munoz, Sergio and Kolosov, Oleg (2021) Thermal transport in enhanced thermoelectric performance high FOM Sb2Te3/MoS2 heterostructure. In: Graphene week 2021, 2021-09-20 - 2021-09-24, Online.

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Abstract

The control of the phonon scattering and the understanding of thermal transport at nanoscale level poses a big challenge in upgrading the efficiencies of nanostructured devices and materials. Furthermore, the lack in analysis of the anisotropic and multi-layered materials restrict the implementation of exotic structures in manufacturing processes. Particularly, for the thermoelectric (TE) devices the understanding of underlying mechanisms of enhancement of phonon scattering paves new pathways for increasing ZTs and enabling efficient commercial applications. In the present study, our aim is to establish the role of multiple interfaces on the thermal transport in Sb2Te3/MoS2 superlattice. We use Scanning Thermal Microscopy (SThM) that provides a flexible approach that can be easily adapted to varying nanoscale structure and geometry of the multilayer sample. In particular, we use a novel approach of cross-sectional SThM (xSThM) that measures the heat transport in the nanoscale sample with the layer of interest is polished using Ar ion beam to produce a damage free nanoscale-flat wedge shaped structure [1]. With the typical wedge angle of about 3-50, two-dimensional xSThM scans map the thermal transport of the Sb2Te3/MoS2 multilayer sample layer as a function of it thickness, allowing to investigate specific contribution of the in-plane and out-of-plane thermal conductivity of the multi-layer samples. In our studies we demonstrate that due to the effective majority carrier filtering and phonon scattering at the potential barrier present at the multiple interfaces, a major enhancement in the value of TE power factor was observed. The present study is important not only for enhancing the TE performance but also helps to establish the efficient approach to quantifying the thermal transport in 2D-3D interfaces, multilayers, as well as in hybrid or buried nanostructures and hence overcome a critical bottleneck in understanding the thermal transport in these complex structures.