Experimental and molecular dynamics simulation study on thermal rectification in multilayer PtSe2

Abstract

Two-dimensional layered materials have attracted increasing attention due to their favorable physical properties. Among them, PtSe2 has good stability and semiconductor–metal junction behavior that can be tuned by thickness, which can be widely used in the fields of thermoelectric devices, transistors, and thermal management devices. Research on the thermal properties of PtSe2 can not only provide a reference for the design of micro–nano thermal devices, but also provide ideas for solving the problem of thermal runaway of the devices, and improve the lifetime and stability of the device. In this study, the in-plane thermal conductivity of the PtSe2 film was investigated by the suspended device method. Low-frequency phonons in PtSe2 contribute significantly to its thermal conductivity. The thermal conductivity decreases from 26.2 W/m K at 300 K to 16.9 W/m K at 470 K due to the enhanced phonon scattering. The phenomenon of thermal rectification (TR) occurs when the heat flux traverses the five-layer trapezoidal PtSe2 film from different directions, resulting from the disparity in phonon spectra. As the temperature increases, the degree of mismatch in the phonon spectra decreases, resulting in a reduction in the thermal rectification coefficient from 16.43% at 300 K to 7.22% at 371 K. The related experimental and simulation results can provide theoretical and data guidance for the design of PtSe2-based micro–nano devices.