ICT2014 Abstracts

Thermoelectric property of 5% indium doped polycrystalline SnTe was investigated from 5 K to 300 K. The carrier concentration and electrical conductivity of parent compound SnTe are very  high due to the intrinsic Sn vacancy. Indium substitution of tin increases the hole carrier concentration to a much higher level and hence  depresses the thermopower substantially. By adding a small amount of extra Te in the Indium doped samples, a sharp increase of thermopower at room temperature was observed. We found that the samples with the highest thermopower have  similar carrier concentration to the  undoped SnTe at room temperature. The significantly improved thermopower is attributed to possible resonant impurity bands introduced by indium. We observed vacancy defects in a structural analysis of these materials by the Scanning Transmission Electron Microscopy (STEM). These localized vacancies  are  believed to be responsible for the reduction of thermal conductivity in the doped samples.  Thermoelectric figure of merit zT was improved in these indium doped samples reaching 0.17at room temperature.