Synthesis and characterization of spin coated ZnTe thin films for improving the efficiency of ZnTe/ZnS solar cell...

Cadmium telluride (CdTe) absorber layer in solar cells (SCs) is environmentally dangerous for the toxic behavior of cadmium (Cd). Alternatively, zinc telluride (ZnTe) is deliberated as a promising PV material for its adoptable absorption coefficient, better conversion efficiency and low production cost of materials requirements. The main objective of this study is to synthesis and characterization analysis of ZnTe thin films to enhance the performance of ZnS/ZnTe solar cell. The structural, optical, morphological and compositional properties of the ZnTe thin films were investigated by X-ray diffraction, UV-visible spectroscopy, scanning electron microscopy, and energy dispersive spectroscopy. The performance of the cell was analyzed by SCAPS-1D. The XRD results showed that all the spin coated ZnTe thin films are in cubic phase. The determining optical band gap values are in the range of 1.77-2.18 eV. The SEM images indicated that the surface of ZnTe thin film annealed at 400 °C has better surface coverage area with homogeneity, good uniformity, and minimum void compared to the other annealed samples. The EDS study exhibits that all the films are Te richness with p-type conductivity. The highest power conversion efficiency (PCE) is found 17.45% with V _oc of 1.41 V, J _sc of 14.01 mA cm^-2 and FF of 88.53% for the 1184 nm optimum thickness of ZnTe and annealed at 400 °C. zinc sulfide (ZnS), indium tin oxide (ITO), platinum (Pt) and aluminum (Al) are indicated as buffer layer, transparent conductive oxide, back metal and front metal respectively of the device. All the findings confirmed that the deposited ZnTe thin films are suitable for usage as an absorber layer in thin film solar cells (TFSCs).