Thermoelectric properties of Pb_(1-x)Cd_xSe crystals grown by vertical bridgman method

摘要

Single crystals of Pb_(1-x)Cd_xSe compounds with x = 0, 0.01, 0.03, 0.05, 0.07 and 0.1 were grown by vertical Bridgman method. The crystalline phase and stochiometry for these crystals were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron-probe microanalysis (EPMA). The thermoelectric behaviors for the Pb_(1-x)Cd_xSe crystals were studied by means of thermal and carrier transport measurements in the temperature range between 50K and 400K. X-ray diffraction and SEM analysis confirmed that as-grown Pb_(1-x)Cd_xSe crystals are simgle phase. The experimental results showed that the PbTe sample is p-type semiconductor but Pb_(1-x)Cd_xSe samples with x = 0.01, 0.03, 0.05, 0.07 and 0.1 are n-type semiconductors. Temperature dependences of resistivity, Seebeck coefficient, and thermal conductivity for the various compositions of Pb_(1-x)Cd_xSe were analyzed. The dimensionless thermoelectric figure of merit ZT for these compounds was evaluated and discussed. It was found that Pb_(0.95)Cd_(0.05)Se exhibits the best thermoelectric performance. The maximum figure of merit (ZT) of Pb_(0.95)Cd_(0.05)Se is about 0.4 7 at 290 K.