Influence of Zn incorporation in CdS: Structural and morphological studies

• CdxZn1−xS thin films by CBD.
• Influence of Zn incorporation in CdS.
• Blue shift in band gap with Zn enrichment.

In recent years, cadmium zinc sulfide (CdxZn1−xS  ) alloy compounds have been paid much attention in the fields of opto-electronics, particularly in photovoltaic devices. In this report, the structural, morphological and optical properties of CdxZn1−xSCdxZn1−xS films deposited by chemical bath deposition (CBD), which is a very attractive method for low-cost and large-area solar cell applications, has been presented. The as-grown layers were characterized using XRD, EDAX, FESEM, TEM and UV–vis spectrophotometers. Structural characterization by X-ray diffraction and SAED measurement reveals a dominant cubic structure with a minor hexagonal phase for high zinc content films. EDAX analysis shows nearly stoichiometric films with cadmium excess. Close packed and less dissociated surface morphology was observed in the CdxZn1−xSCdxZn1−xS ternary thin films with lower Zn2+Zn2+ content than the higher Zn2+Zn2+ content one. Agglomeration of nanocrystals for high zinc content films results in enhanced absorption. The mean grain size of Cd0.5Zn0.5SCd0.5Zn0.5S calculated from TEM image is ~15 nm. Optical absorption study exhibits a distinct blue shift in band gap energy with enhancement of zinc content in the film.