Unraveling Thermal Transport Properties of MoTe₂ Thin Films Using the Optothermal Raman Technique

Understanding phonon transport and thermal conductivity of layered materials is not only critical for thermal management and thermoelectric energy conversion but also essential for developing future optoelectronic devices. Optothermal Raman characterization has been a key method to identify the properties of layered materials, especially transition-metal dichalcogenides. This work investigates the thermal properties of suspended and supported MoTe₂ thin films using the optothermal Raman technique. We also report the investigation of the interfacial thermal conductance between the MoTe₂ crystal and the silicon substrate. To extract the thermal conductivity of the samples, temperature- and power-dependent measurements of the in-plane E_2g¹ and out-of-plane A_1g optical phonon modes were performed. The results show remarkably low in-plane thermal conductivities at room temperature, at around 5.16 ± 0.24 W/m·K and 3.72 ± 0.26 W/m·K for the E_2g¹ and the A_1g modes, respectively, for the 17 nm thick sample. These results provide valuable input for the design of electronic and thermal MoTe₂-based devices where thermal management is vital.