Bandgap tailoring in CdxZn1 − xS alloy films deposited by successive ionic layer adsorption and reaction

The paper reports tailoring of the optical bandgap in SILAR deposited CdxZn1-xS alloy films. Acetates and chlorides of zinc and cadmium were used to obtain the films. Two separate routes were employed to achieve desired alloy composition in the films. In the first route, the molar concentration of the precursors was varied. In the second route; various volumes of precursors (with fixed concentration) were used. The films were polycrystalline with predominant hexagonal phase. The bandgap of the films varied from 2.4 eV to 3.5 eV. This bandgap range is highly optimum for the window layer in solar cells and other optoelectronic applications. Variation in the bandgap was studied as a function of alloy composition. The bowing parameter of the bandgap variation was found to be different for two routes chosen to deposit the films.