Structural, photoluminescence and electrical properties of MW-CBD CdZnS thin films

Thin films of CdZnS have found extensive applications in various optical, electrical and optoelectronic devices. A simple method of microwave assisted chemical bath deposition (MW-CBD) has been used to deposit CdZnS (Cadmium Zinc Sulphide) thin films. The bath solution is composed of Cadmium Sulphate, Zinc Sulphate, thiourea, ammonium Sulphate and ammonia. The concentration of bath solution is varied as Y=0.1, 0.3 and 0.5 where Y=[ZnSSO₄]/ {[CdSSO₄] + [ZnSO₄]}. Deposition has been carried out for 120s microwave irradiation time. X-ray diffraction (XRD) indicates the hexagonal structure (002) reflection for the as-deposited CdZnS thin films. Grain size, dislocation density and strain in the deposited films have been determined. High resolution scanning electron microscopy (HRSEM) image gives the morphology, size and shape of particles in the deposited CdZnS thin films. Secondary ion mass spectrometry (SIMS) results show that composition is uniform throughout the entire film thickness. Band gap of deposited films as determined by photoluminescence (PL) studies is found to increase from 2.40 eV to 2.47eV with the increase in Y from 0.1 to 0.5. Ohmic conduction and space charge limited conduction (SCLC) has been observed in the deposited films.