Study of SnO2/CdSexTe1-x/CdTe Solar Cells Fabricated by Selenium Treatment of the Absorber Layer

The reboot after the global Covid-19 crisis will go through the investment of large economic resources around the world. To take advantage of the opportunity to improve the world situation, this money should be invested extensively for the technological and green energy revolution. Photovoltaics is nowadays a mature technology, capable of providing green energy at competitive prices compared to fossil fuels. Regarding manufacturing costs, CdTe thin film devices have a great advantage over traditional crystalline silicon cells, since they can be fabricated in a single production line. Furthermore, CdTe panels nowadays exceed an efficiency of 19 %, close to that of silicon technology. The efficiency improvement of the last few years is mainly due to the introduction of a CdSexTe1-x layer in the absorber. This reduces the band gap increasing the absorption in the long wavelength region. Moreover, it allows a better band alignment with wider band gap buffers, enabling the removal of the CdS window layer. In this work we study a SnO2/CdSexTe1-x/CdTe solar cell where the band gap grading of the absorber has been achieved through an innovative method: the selenization of the CdTe layer.