Unraveling Thermal Transport Properties of MoTe 2 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 MoTe 2 thin films using the optothermal Raman technique. We also report the investigation of the interfacial thermal conductance between the MoTe 2 crystal and the silicon substrate. To extract the thermal conductivity of the samples, temperature- and power-dependent measurements of the in-plane E 2g 1 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 2g 1 and the A 1g modes, respectively, for the 17 nm thick sample. These results provide valuable input for the design of electronic and thermal MoTe 2 -based devices where thermal management is vital.