Thickness Optimization of ZnO/CdS/CdTe Solar Cell by Numerical Simulation

CdTe based solar cells with high efficiency alternative to solar cells from elemental semiconductors is an important work carried out over the decades. However, the research has not yet yielded the highest possible efficiency with CdTe absorber. Selection of suitable window layer and optimizing the thickness of the different layers is still a quest in researchers. Numerical simulation of the different material combinations can speed up the research work. In this regard, numerical simulation is an essential tool to find the optimized structure for the enhanced device performance. In the present work, the thicknesses of window and absorber layers, one of the crucial factors that affect the solar cell performance, are tuned for ZnO/CdS/CdTe system. In case of CdS/CdTe solar cells, spectral loss created by CdS lowers the cell efficiency. Concept of bilayer window is useful to minimize the loss at window layer. Hence the ZnO/CdS bilayer window is adopted and demonstrated that the cell efficiency can be increased up to 17.66% with current density of 28.4 mA/cm² and 73.7% fill factor.