Mossbauer emission spectroscopy of the Ga-67(Zn-67) isotope was used to sho
w that the two-electron acceptor impurity of Zn is present in silicon only
in the form of neutral (Zn-0) or doubly ionized (Zn2-) centers, depending o
n the Fermi-level position. Broadening of the spectra corresponding to the
above centers indicates that the local symmetry of these centers is not cub
ic. The absence of the line corresponding to the singly ionized state (Zn2-
) of zinc in the Mossbauer spectra of partially compensated samples is rega
rded as evidence that the correlation energy is negative. (C) 2000 MAIK "Na
uka/Interperiodica".