Measurement of Thermoelectric Properties of Semimetallic Polycrystal PtSe₂ Film with Temperature Dependence

Hardness of measuring thermoelectonic properties of nm-scale thinckness thin film structure is one of the obstacles to research TMDC materials. We used a suspended bridge-type method and a strain gauge-controlled suspend platform to observe in-plane thermal conductivity and Seebeck coefficient of large-area platinum diselenide (PtSe₂) thin film. We founded influence about thermoelectric properties differency with thickness and christality changes. We observe the greatly suppressed in-plane thermal conductivity for 11-nm-thick polycrystalline PtSe₂ film as compared to that of exfoliated similar-thick in-plane single-crystalline PtSe₂ layer at 300 K. This reduction is attributed to the enhanced phonon scattering in polycrystalline PtSe₂ thin film. Our finding can pave the way toward an effective strategy for promising large-area TE energy harvesting devices with a high figure of merit in 2D semimetallic transition metal dichalcogenide materials.