Microcrystalline silicon solar cell using p-a-Si:H window layer deposited by photo-CVD method

A p-a-Si:H layer, deposited by a photo-assisted chemical vapor deposition (photo-CVD) method, was adopted as the window layer of a hydrogenated microcrystalline silicon (μc-Si:H) solar cell instead of the conventional p-μc-Si:H layer. We verified the usefulness of p-a-Si:H for the p-layer of the μc-Si:H solar cell by applying it to SnO₂-coated glass substrate. It was found that the quantum efficiency (QE) characteristics and solar cell performance strongly depend on the p-a-Si:H layer thicknesses. We applied boron-doped nanocrystalline silion (nc-Si:H) p/i buffer layers to μc-Si:H solar cells and investigated the correlation of the p/i buffer layer B₂H₆ flow rate and solar cell performance. When the B₂H₆ flow rate was 0.2 sccm, there was a little improvement in fill factor (FF), but the other parameters became poor as the B₂H₆ flow rate increased. This is because the conductivity of the buffer layer decreases as the B₂H₆ flow rate increases above appropriate values. A μc-Si:H single-junction solar cell with ZnO/Ag back reflector with an efficiency of 7.76% has been prepared.