A numerical simulation study of ZnTe-based solar cells

Solar cells based on II-VI semiconductors are among the leading candidates for low-cost photovoltaic conversion of solar energy due to their high absorption coefficients and therefore the low material consumption for their production. To understand the basics of photovoltaic (PV) cells, several types of simulation software are available. This work reports on the analysis of Zinc Telluride (ZnTe) thin films solar cells by using Solar Cell Capacitance Simulator software (SCAPS). Dark and illuminated I-V characteristic analyzed. These results are useful for understanding the fundamentals of PV devices as well as a feedback for designers and producers of high efficiency ZnTe cells. The state of the arts combination of the cell is consists of ZnTe absorber layer, CdS as buffer and ZnO as optical window following the sequence ZnTe/CdS/ZnO. Simulation studies by varying several solar cell parameters such as thickness of various layers reveal that increasing the thickness of absorber layer results in higher efficiency. Solar cells based on standard ZnTe absorbers give conversion efficiencies about 8 % due to the high bandgap value of the absorber. However, if the absorption coefficient is modified to take into account the presence of an Intermediate Band, like in ZnTe:O absorbers, the overall performance of PV devices increases dramatically and the conversion efficiency provided by SCAPS is close to 60 %.