Effect of hydrogen dilution on the open-circuit voltage of hydrogenated amorphous silicon solar cells

The open-circuit voltage (Voc) of hydrogenated amorphous silicon solar cells has been studied experimentally and by computer simulation. We find that band gap and defect states affect Voc significantly. Hydrogen (H2) dilution widens the band gap and reduces density of defect states; both contribute to larger Voc and better fill factor in H2 diluted solar cells. Valence band tail narrowing could affect Voc, but is not included in this study due to lack of available data.