The influence of crystallization conditions and postcrystallization processes on the real structure of PbTe-based solid solutions

T.A. Kuznetsova, S.G. Dorofeev, O.I. Tananaeva, V.P. Zlomanov

Forth International Conference on Materials Science and Material properties for Infrared Optoelectronics (Kiyv, Ukraine, 1998), p. 164.

The influence of the crystallization conditions and postcrystallization processes on the real structure of PbTe-based semiconductor solid solutions was studied. The crystallization conditions were varied by the change of the limiting stage (mass transfer in the vapor or surface kinetics) during the vapor-liquid-crystal growth. The postcrystallization processes were simulated by means of isothermal annealing of slices of crystals at temperatures coinciding with the temperature of the ending of the growth process. The crystallization conditions for different limiting stages were determined in kinetic experiments by comparison of weight and length of crystals grown at different temperatures, as a function of the length of the mass transfer way and cross section of ampoules. The character of components distribution in Pb$_{0.75}$Sn$_{0.25}$Te crystals was found to depend on the growth limiting stage. The postcrystallization processes were studied on PbTe crystals doped with Cr, Co, Ni, and In, which were grown at different supersaturations and had different real structure. Auger electron spectroscopy, selective etching, measurement of Hall effect were used in these studies. The structure and composition of the surface of crystals, the concentration of charge carriers, and the features of real structure were found to change during the annealing. The evidences of the concentration supersaturation were found to transform during the postcrystallization. The real structure of samples with low impurity concentration and dislocation density of (1-2)*10^4$~cm$^{-2}$ exhibits minimal changes during the annealing. The work was supported by RFBR grant No. 96-03-32932.

Laboratory of Physics and Chemistry of Semiconductors