Improvement of open circuit voltage in microcrystalline silicon solar cells using hot wire buffer layers

In a wide range of crystallinity between 60% and 10%, microcrystalline silicon (μc-Si:H) solar cells with i-layers deposited by hot wire chemical vapour deposition (HWCVD) exhibit higher open circuit voltage and fill factor than the cells with plasma enhanced (PE-) CVD i-layers. Inserting an intrinsic μc-Si:H p/i buffer layer prepared by HWCVD into PECVD cells nearly eliminates these differences. Using this buffer layer concept allows the authors to apply high deposition rate PECVD processes for the μc-Si:H i-layer material yielding a high efficiency of 10.3% for a single junction μc-Si:H solar cell.