Carrier-type reversal in Pb-Ge-Se glasses: Photopyroelectric measurements of thermal conductivity and heat capacity

The thermal conductivity and heat capacity of Pb modified Ge-Se glasses, Pb 20GexSe80-x (x=17-24) and PbyGe42-ySe58 (y=0-20), which exhibit carrier-typ e reversal from p type to n type at specific compositions, have been measur ed simultaneously by the photopyroelectric technique. The thermal conductiv ity as well as the heat capacity show anomalous variations at the compositi ons at which carrier-type reversals are reported to occur in these glasses. The results are explained in terms of the enhancement in electron concentr ation during p- to n-type changeover in these materials. (C) 2001 American Institute of Physics.