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

Microcrystalline silicon-based single-junction p-i-n solar cells have been fabricated by very high-frequency plasma enhanced chemical vapor deposition using a shower-head 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% (V-oc = 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 10(15) cm(-3) range. In spite of the presence of oxygen contamination, good electrical properties and good infrared cell response are obtained. Copyright (C) 2006 John Wiley & Sons, Ltd.