The reflectivity and photoconductivity spectra of Cd1-xFe xTe in the 1.0-30.0 eV energy range

The reflectivity and photoconductivity spectra for mixed crystals Cd 1-xFexTe (0.00<or=x<or=0.05) have been investigated. The reflectivity measurements have been carried out in a wide energy range-1.0-30.0 eV at 300 and 77 K. The photoconductivity spectra have been taken in the 1.0-3.0 eV range at 300 K. The analysis of the energy positions of maxima in reflectivity and photoconductivity spectra as a function of the Fe concentration allowed us to confirm the existence of the deep donor-like state predicted by the band-structure model of these compounds. Using the photoconductivity data the value of 0.08 eV above the top of the valence band for the energy position of this deep donor-like state was found. The influence of Fe2+(3d6) states on the changes in the energy positions of the reflectivity maxima E0, E1, E1 + Delta 1, E2, E1', E1'+ Delta , c, d, e, f, h and i has been analysed and the results obtained are consistent with the models existing in the literature.