Increasing the Efficiency of the In-Plane Seebeck Effect in the Homostructure Through O2 Plasma Treatment on the PtSe2 Surface

Transition metal dichalcogenide (TMDC) films have garnered significant attention in the semiconductor field due to their exceptional thermoelectric properties. When TMDCs are stacked in multiple layers and bonded by van der Waals forces to form a homo- or heterostructure, these materials exhibit unusual thermoelectric characteristics. In our research, we employed PtSe2 as a 2D TMDC material and created a PtSe2/PtSe2 (3 nm/3 nm) homostructure. Prior to stacking the PtSe2 layers, the surfaces were subjected to O2 plasma treatment, inducing vacancies at the junctions between the PtSe2 layers. We investigated the effect of these vacancies by preparing several samples with varying O2 plasma treatment durations and measuring the in-plane Seebeck effect in each sample. The presence of vacancies facilitates the exchange of momentum by charge carriers, driven by the temperature gradient in the vertical direction. As a result, the electrical conductivity remains unaffected even as the stacked structure thickens, while the Seebeck coefficient is enhanced.