High-efficiency µc-Si solar cells made by very high-frequency plasma-enhanced chemical vapor deposition

Abstract

Microcrystalline silicon-based single-junction p–i–n solar cells have been fabricated by very high-frequency plasma enhanced chemical vapor deposition using a showerhead cathode at high pressures and under silane depletion conditions. The i-layers are made near the transition from amorphous to crystalline. It was found that, especially at high crystalline fractions, the open-circuit voltage and fill factor are very sensitive to the morphology of the substrate. At an i-layer deposition rate 0·45 nm/s, we have measured a stabilised efficiency of 10% (Voc = 0·52 V, FF = 0·74) for a cell made on texture-etched ZnO:Al. The performance is stable under light soaking. The defect density of the absorber layer is in the 1015 cm−3 range. In spite of the presence of oxygen contamination, good electrical properties and good infrared cell response are obtained. Copyright © 2006 John Wiley & Sons, Ltd.