Improved μc-Si p-layer and a-Si i-layer materials using VHF plasma deposition

Microcrystalline Si p-layers have been widely used in a-Si solar cell technology to achieve high efficiency. To improve the solar cell performance further, the authors have studied the deposition of high quality μc-Si p-layer material using a modified VHF plasma enhanced CVD process and consequently have improved the solar cell current. This improvement was primarily in the blue response which leads to a 6-10% improvement in the overall solar cell efficiency. In addition, they have explored the deposition of a-Si at high rates using VHF plasma and compared these VHF i-layers with RF plasma deposited i-layers. With improved deposition conditions, VHF intrinsic layers deposited at a rate up to 15 Å/s show similar device performance and light stability to VHF and RF i-layers deposited at low rates and show higher stability than RF i-layers deposited at high rates in the same deposition system. A 10.9% efficient single-junction solar cell was fabricated using a VHF deposited i-layer