STRUCTURAL AND OPTICAL STUDIES IN OXYGENATED AMORPHOUS CDTE-FILMS

Amorphous oxygenated CdTe films (a-CdTe:O) were grown by the radio-frequency sputtering deposition technique in an Ar-N-O atmosphere; by increasing the nitrogen partial pressure in the growth chamber we are able 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 the different samples. X-ray diffraction patterns showed that the incorporation of oxygen leads to the amorphization of the zinc blende lattice. The optical absorption spectra for each sample was measured from optical transmission and photoacoustic techniques, and using the Tauc model for amorphous materials the band gap energy was obtained. From the 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.