Crystallization specificities of bismuth telluride from melt, containing surplus of tellurium

A study was made on effect of crystallization medium on character of defects, arising in growing crystal of Bi2Te3, the nature of current carriers and their mobility. Monocrystals were grown by Czochralski method from the melt of stoichiometric composition (60 at. % Te+40 at. % Bi). Models of defect centers, arising during Bi2Te3 crystallization from melts of diffe-- rent compositions were suggested. It was established that the more was tellurium content in initial melt, the more was the value of charge carrier concentration in samples of p- and n-type grown in series. The mobility of charge carriers in samples of p-type close to the transition region at 77 K had abnormally low values as compared with samples prepared from melt of ctoichiometric composition