FORMATION OF THE BAND GAP OF CdS THIN FILMS GROWTH BY DIFFERENT TECHNIQUES
We studied the formation of the band gap on CdS thin films deposited on glass substrates by chemical bath deposition (CBD) and close spaced sublimation (CSS) techniques. In order to obtain the first stages of films growth, we used small deposition times for both methods. Films growth by CBD were prepared by two modalities on the bath agitation: magnetic agitation with a magnetic stirrer, and a new proposal based on ultrasonic vibration. Morphological, structural, and optical results were obtained on films. Values of the band gap energy obtained by the absorption method, are agree with the values reported in the literature, but squared absorption coefficient vs. energy curves, showed differences between them. An explanation on this behavior with the optical window effects, the surface roughness, the structural results, the films thickness, and the growth technique is given. CBD technique with ultrasonic vibration produces films with more cleaner surfaces and better optical properties.