Evolution of thermal conductivity of In3SbTe thin films up to 550 °C

The temperature dependent thermal conductivity of In-Sb-Te thin films has been measured by modulated photothermal radiometry in the 20-550 °C range for samples with different Te content. Significant changes with temperature are observed and ascribed to a sequence of structural transformations on the basis of in-situ Raman spectra. The data suggest that the as-deposited material consisting of a mixture of polycrystalline InSb0.8Te0.2and amorphous Te first undergoes a progressive crystallization of the amorphous part, mostly above 300 °C. Further increase in temperature above 460 °C leads, for higher Te content in the alloy, to the formation of crystalline In3SbTe2, intertwined with a less conductive compound, possibly InTe and/or InSb. Upon cooling to room temperature, the initial polycrystalline InSb0.8Te0.2phase is mostly recovered along with other compounds, with a slightly higher thermal conductivity than that of the as deposited material.