Thermal transport properties of nanocrystalline Bi–Sb–Te thin films prepared by sputter deposition

Abstract

Grain-size dependent thermal conductivity of sputtered nanocrystalline Bi–Sb–Te thin films was measured by a 3ω method. By changing deposition temperature from 100 °C to room temperature, the mean grain size of the Bi–Sb–Te films decreased from 83 to 26 nm and the lattice thermal conductivity reduced from 0.79 to 0.45 W/mK proportionally. The effect of grain boundary on lattice thermal conductivity can be described by an effective thermal boundary resistance that was determined in the range of 0.56–1.8×10−8 m2K/W for the nanocrystalline Bi–Sb–Te thin films studied.