Influence of deposition temperature and fluorine doping on CdS properties: Exploring applications in CdTe solar cells

CdS and CdS:F thin films were synthesized at 75 degrees C and 90 degrees C by CBD with NH4F as the fluorine dopant. The structural, morphological, optical, and electrical properties were investigated with varying F wt.%. XRD analysis revealed a coexistence of cubic and hexagonal phases with small crystallite sizes. Raman spectroscopy exhibited characteristic peaks of 1LO and 2LO, corresponding to longitudinal optical phonons. Scanning electron microscopy (SEM) images displayed dense films with excellent substrate adhesion and crystalline morphology. Optical analyses unveiled noticeable alterations in optical transmittance due to F doping, with bandgap values ranging between 2.3 to 2.4 eV. Electrical resistivity, typically in the order of k Omega cm, was influenced by incorporating F atoms within the CdS lattice. Notably, the fabrication of CdS/CdTe solar cells yielded efficiencies of 5.53 % for undoped CdS films and 7.47 % when utilizing films doped with 0.00455 wt% fluoride, highlighting the beneficial impact of F incorporation on solar cell performance.