STRUCTURAL AND OPTICAL STUDIES IN OXYGENATED AMORPHOUS CDTE-FILMS

Amorphous oxygenated CdTe films (a-CdTe:O) were grown by the radio-fre quency sputtering deposition technique in an Ar-N-O atmosphere; by inc reasing the nitrogen partial pressure in the growth chamber we are abl e to increase the amount of oxygen in the films in the range: 0-66 at. %. Auger analysis indicated that only Cd, Te, and 0 were present in t he different samples. X-ray diffraction patterns showed that the incor poration of oxygen leads to the amorphization of the zinc blende latti ce. The optical absorption spectra for each sample was measured from o ptical transmission and photoacoustic techniques, and using the Tauc m odel for amorphous materials the band gap energy was obtained. From th e analysis of the structural and optical measurements we propose that the a-CdTe:O films are ternary semiconductors described by the formula : [CdTe]1-xOx, and that they do not show evidence of any phase mixture and/or precipitates.