The significant role of ZnSe layer thickness in optimizing the performance of ZnSe/CdTe solar cell for optoelectronic applications

• This work details the structural and optical properties of ZnSe layer. • This work demonstrates the role of ZnSe layer film in improving fabricated ZnSe/CdTe solar cell. • In this work, the series and parallel parasitic resistances are decreased with the increase of film thickness. In this framework, the ZnSe layer was prepared via the well-known thermal evaporation method at various thicknesses. The thicknesses of the ZnSe layer were monitored by the quartz crystal monitor type (FTM4, Edwards). The influence of ZnSe film’s thickness on the structure, optical and electrical properties were studied. Using XRD patterns, the structural parameters of the ZnSe layer have been calculated. It is observed that the crystallite size increases as the film thickness increases, but the lattice strain decreases. SEM measurement results show that as the thickness of the ZnSe film increases, the grain size improves. The electrical properties of ZnSe films at various thicknesses have been measured via a standard four-point probe method. It can be noticed that as the ZnSe film’s thickness increases, the electrical conductivity also increases. This means that ZnSe film with higher electrical conductivity will be more suitable for the high-efficiency ZnSe/CdTe solar cell. In a higher absorption region for both T (λ) and R (λ), the absorption coefficient has been determined, and thus the optical energy gap, which is increased from 2.62 to 2.91 eV. At the same time, the effect of the ZnSe layer with different thicknesses on the performance of the ZnSe/CdTe solar cell was discussed. The figure of merit has been computed to determine the quality of the thin films. The parameters of the hetero-junction have been measured, such as the correction ratio, which is improved by increasing the film’s thickness. The junction resistance and parasitic resistance were also calculated which is decreased with increasing of the thickness film, thereby improving the performance of fabricated ZnSe/CdTe solar cell.