Аннотации:
The reflection and transmission spectra (in the range from 300nm to 1400nm) were recorded using a PMQ – II (Carl Zeiss, Jena) spectrophotometer. The absorption coefficient, was determined from transmission spectra. The values of optical band gap, Eg, have been determined by extrapolating the linear portions of curves (ahv)2 = f(hv) for (ahv)2 - 0. For the analised samples these values (Eg = 2.68 – 3.5eV) are in a good agreement with the values of band gap energy obtained for bulk crystals.