Effects Of Oxygen Incorporation In Solar Cells With A-Siox:H Absorber Layer

The effects of oxygen incorporation on layer properties and cell performance were investigated in thin film solar cells with a-SiOx:H absorber layers. Besides the widened optical band gap and increased defect densities, a doping effect is observed upon oxygen incorporation even for the layers with wide band gap. From comparison of solar cells illuminated from either p-or n-side, we conclude that overall hole carrier collection is strongly deteriorated by increasing the oxygen concentration. The donor-like states induced by oxygen reform the electric field in the absorber. The intensified electric field near the p/i interface improves the quantum efficiency (QE) around 400 nm, which is attributed to the better carrier collection in the p-layer. The maximum of QE shows a blue shift with both p-and n-side illumination. It is consistent with the enhanced optical band gap of the absorber layer and shows the potential of usage in multi-junction solar cells. (C) 2015 The Japan Society of Applied Physics