| Faced with an ever-increasing energy demand, the earth's sources of non-renewable energies are not expected to last long. Among the many contenders vying to replace fossil fuels, photovoltaic (PV) solar cells offer many advantages, including needing only little maintenance and being environmentally friendly. However, the major drawback up to date has been their cost. In order for PV to be viable for large-scale energy conversion, their efficiency and reliability must be improved whilst making them cheaper. Cadmium Sulfide/Cadmium Telluride (CdS/CdTe) solar cells have been studied extensively for those reasons. Their advantage lies in their very low fabrication cost, which can be as low as {dollar}3/W in mass production[1]. Their disadvantages are the relative low conversion efficiency and stability compared to other solar cell types. One main limiting factor in this cell type is the US window layer, which absorbs light but does not convert it into electricity. Therefore, high efficiency PV cells try to minimize the US absorption by using ultra thin US layers. However, too thin of a US layer can lead to low voltage devices and yield other problems. (Abstract shortened by UMI.)... |
