Microcrystalline silicon solar cells made using RF, MVHF, and microwave at various deposition rates

Three glow-discharge techniques have been used to deposit /spl mu/c-Si:H solar cells at various rates. Conventional RF glow discharge is used to explore the highest efficiency of /spl mu/c-Si:H single-junction and multi-junction solar cells at a low rate /spl sim/1.0 /spl Aring//s. Our best a-Si:H//spl mu/c-Si:H double-junction cell so far exhibits an initial active-area efficiency of 13.0%. Modified VHF glow discharge is used to optimize /spl mu/c-Si:H solar cells at high rates /spl sim/3-10 /spl Aring//s. An initial active-area efficiency of 12.3% has been achieved in an a-Si:H//spl mu/c-Si:H double-junction structure, where the intrinsic /spl mu/c-Si:H layer is deposited in 50 minutes. Light soaking experiments showed that a bottom-cell limited current mismatch in a-Si:H//spl mu/c-Si:H double-junction cells is desirable for stability. Stable active-area efficiencies of 11.2% and 10.4% have been achieved using RF and MVHF deposited a-Si:H//spl mu/c-Si:H double-junction structures, respectively. Very high rate (20-30 /spl Aring//s) deposition of /spl mu/c-Si:H solar cells using microwave glow discharge shows encouraging results.