Study on the Influence of Thickness and Temperature on the Thermoelectric Properties of Sputtered Molybdenum Disulfide Films

Abstract

Molybdenum disulfide (MoS2), a promising two-dimensional material, has attracted significant attention due to its unique electronic and thermal properties, making it a potential thermoelectric material. However, there is currently limited research on the effects of thickness and temperature on the thermoelectric properties of MoS2 films prepared by magnetron sputtering. In this paper, MoS2 films with different thicknesses were first deposited using magnetron sputtering, ranging from 43 nm to 231 nm. The Frequency Domain Thermoreflectance (FDTR) system was established to measure the thermal conductivity of MoS2 film and an analysis of the sensitivity of the measurements was conducted. The experimental results indicate a thermal conductivity range of 0.49 to 0.53 W/m·K, with thickness showing minimal impact. The thermal boundary conductance between the sputter-deposited MoS2 film and the SiO2 substrate is measured at 12 ± 5 MW/m²·K. The electrical conductivity and Seebeck coefficient were measured in the temperature range of 300 K to 450 K using LSR-3 equipment. The results indicate that the MoS2 films prepared in this study were all p-type semiconductors, with electrical properties increasing with temperature. Additionally, based on the measured results of the Seebeck coefficient in this study, a simplified model for fitting and predicting the film's Seebeck coefficient was proposed. The fitting deviation was 7%, and the prediction deviation was 19%. Within the temperature range of 300-430 K, the power factor of all films increases with the rise in temperature, reaching a maximum value of 0.36 µW/cm·K.

Keywords: Molybdenum Disulfide, thermal conductivity, frequency-domain thermoreflectance, Seebeck Coefficient