Radiative defects in undoped and Ge-doped wafers were studied by means of cathodoluminescence spectroscopy and scanning electron microscopy, before and after annealing in HgI2 vapor (250C, 24 or 48h). It was shown that annealing led to the growth of an -HgI2 polycrystalline layer on the wafer surface, and this acted as a getter for Te precipitates which were distributed randomly throughout the entire volume of the as-grown wafers. The annealing mainly affected the cathodoluminescence bands which were related to Te vacancies (with a band at about 1.00eV) and Ge dopants (bands at 0.82 and 0.89eV). The contribution of the latter to the total luminescence emission decreased after annealing.

G.Panin, J.Piqueras, N.V.Sochinskii, E.Dieguez: Materials Science and Engineering B, 1996, 42[1-3], 277-83