High efficiency large area solar cells using microcrystalline silicon

We made a substrate type triple junction solar cell by using roll-to-roll PCVD machines. The triple junction solar cell consists of stainless steel substrate, silver (Ag)/zinc oxide (ZnO) back reflector, microcrystalline silicon (/spl mu/c-Si) bottom cell, microcrystalline silicon middle cell, amorphous silicon (a-Si) top cell, transparent conductive oxide layer (TCO), positive electrode and transparent hard coat layer. Microcrystalline silicon intrinsic (i) layer and amorphous silicon intrinsic (ii) layer are deposited with VHF PCVD. The deposition rate of /spl mu/c-Si is 1.0 to 3.0 nm/sec. The cell area is 801.6 cm/sup 2/, including grid electrode area. We obtained a 13.4% initial cell efficiency at the area. The initial degradation rate is about 5%.