The parameters of formation of vacancies in crystals of elements of the C sub-group (diamond, Si, Ge, α-Sn, Pb) were calculated. The method used took account of both quantum effects at low temperatures and the delocalization of atoms at higher temperatures. It was shown that the consideration of atom delocalization brought about an increase in the values of enthalpy and entropy and the volume of vacancy formation. At low temperatures, the parameters of vacancy formation depended heavily upon temperature, with the entropy of vacancy formation becoming negative. In the high-temperature region, good agreement was obtained with both experimental data and theoretical estimates reported in other publications. The dependence of vacancy-related parameters upon temperature during the course of isobaric heating of diamond in the range from 100 to 4500K was studied. The limits of applicability of the Arrhenius equation with a temperature-independent energy of the activation process were considered. It was shown that there was a correlation between the entropy and enthalpy of vacancy formation, and between the volume and entropy of vacancy formation over the entire temperature range studied.

Parameters of Vacancies’ Formation in the Carbon-Subgroup Crystals. M.N.Magomedov: Semiconductors, 2008, 42[10], 1133-45