Thermal and electrical properties of Czochralski grown GeSi single crystals

The thermoelectric parameters, thermal conductivity, electrical conductivit y and Seebeck coefficient of high quality single crystals of Ge1-xSix alloy s in various composition of 0.8 < x < 1, were investigated in the temperatu re range 300-1000 K for application to a high performance thermoelectric de vice. Single crystals of the alloys of heavily impurify-doped were grown by the Czochralski technique. The thermal conductivity was mainly controlled by phonon scattering, showing a minimum at x = 0.5-0.6. The electrical cond uctivity of alloys was well controlled to be almost constant with a high ma gnitude by the suitable doping level. The Seebeck coefficient was 300-400 m uV/K at 600 degreesC in the impurity-doped GeSi alloys. The dependence of t he Seebeck coefficient on the electrical conductivity was revealed. The dim ensionless figure of merit of 0.65 was evaluated in the impurity-doped sing le crystals of GeSi alloys. (C) 2001 Elsevier Science Ltd. All rights reser ved.