Thermoelectric properties of Sn doped GeTe thin films

The feasibility of using GeTe based alloys in thermoelectric power generation has received a revived interest and has been extensively investigated through the approach of substitutional doping in recent times. Here, a systematic study of the thermoelectric properties of Sn doped GeTe prepared by DC magnetron co-sputtering using Sn and GeTe targets is presented. The effect of variation in Sn content was studied on the chemical bonds and of as-deposited films. Thermoelectric properties of as-deposited and fast annealed thin films at 280 °C in vacuum were measured. It is found that Sn forms bond with Te and increasing Sn content decreases the band gap of amorphous samples. The power factor was enhanced both at low temperature and high temperature through the reduction of the electrical resistivity and enhanced seebeck effect caused by changes in the carrier effective mass and carrier concentration. A competitively high power factor of 2.789 × 103 μW/K2m is reached at 300 K for the amorphous films and 1.423 × 103 μW/K2m at 718 K for the crystalline film. This provides a good basis for further enhancement of the power factor.