Generateur Photovoltaique au Silicium Amorphe Hydrogene

Summary

The purpose of this work is to realize by R.F. sputtering two stacked photovoltaic structures in view of increasing the conversion efficiency of hydrogenated amorphous silicon solar cells. The dual Schottky structure must enhance the short-circuit current Jcc by an electrical parallel connection of two diodes, while the twin (dual) p-i-n structure must double the open circuit voltage Voc by in-series connecting two junctions. We have first elaborated elementary Schottky and p-i-n diodes which have been electrically investigated. P-i-n diodes offer better Voc but weaker Jcc than Schottky diodes. Good tunnel junctions have been realized and have allowed to double the value of Voc in stacked p-i-n structures. On the other hand, the attempt to make dual Schottky structures was not successful, resulting in low Voc values without any increase of Jcc. These results prove that an effective enhancement of the efficiency will be possible only with multispectral stacked junctions.