Investigation of the effect of annealing conditions on electrodeposited CdTe thin films from non-aqueous bath

We have investigated the effect of annealing conditions onto the cadmium telluride (CdTe) layers obtained using potentiostatic electrodeposition from non-aqueous electrolyte. A conventional three-electrode geometry consisting; working (FTO), counter (Platinum) and reference (Ag/AgCl) electrodes were employed. The samples electrodeposited at − 0.625 V were annealed at 420 °C and cooled down with different procedures. The samples were characterized to study the structural, optical, morphological, compositional and transport properties. Quenched sample is found better as compared to naturally cooled and as-deposited samples. Growth of cubic polycrystalline crystal structure with improved crystallinity of CdTe is revealed from annealed samples. Highly stoichiometric CdTe layers with densely packed globular surface morphology of particle size ~ 2 μm obtained upon annealing the samples is proposed to be suitable for high efficiency thin film solar cells (TFSCs). The micro-structural Raman analysis supports the increased crystallinity and stoichiometric growth of sample after annealing. Highly ohmic behavior with higher carrier concentration and ideality factor measured for quenched samples is reported to be associated to sink in grain boundaries due to grain growth results the densification of sample leads to less defective layers. The results imply that annealing conditions have significant impact on the properties of CdTe samples and the quenched films may be most appropriate as an absorber layer for TFSC applications.