Evidence of scattering effects on the thermal transport in indium-doped CdTe films

Photoacoustic (PA) heat transmission measurements were used to study thermal transport in n-type polycrystalline CdTe films doped with metallic indium. Thermal diffusivity (TD) at room temperature was determined using an open cell PA technique. The TD obtained for each sample was correlated with x-ray diffraction measurements. It can be shown that the TD of the undoped films under investigation is significantly reduced compared with corresponding doped films. This reduction is a result of the high concentration of indium atoms and defects depending on the deposition parameters. It is shown that the effects of CdTe lattice shrink produced by indium doping, induces an increase in phonon scattering reflected in the large TD decrease even with moderated indium concentration. We have calculated the relation between the TD and the lattice parameter as a polynomial function (cm² s^-1) = -35225.2+14259a-1532.7a²-27.9a³+8.4a⁴.