Low Cost TCO Technology for a-Si Thin Film Solar Cell

We have developed large scale (1100×1300mm) in-house ZnO TCO using SDCVD (Space Divided Chemical Vapor Deposition) to substitute commercialized SnO2:F based TCO. In-house ZnO TCO was investigated based on the low cost soda lime glass and was compared with SnO2:F TCO based on the low iron white glass for the application of a-Si solar cell. Boron and hydrogen were used as a co-dopant to control electrical properties. Post treatment using hydrogen plasma was performed in order to boost the effect of co-doping. Co-doping was proved to have a positive effect on FF and Jsc compared to boron single doping. Electrical characteristics showed the sheet resistance of ZnO around 8Ω/ with minimum value of 6Ω/ at the thickness of 1.2 . Optical properties showed the transmittance more than 91.3% and the haze of 5.7% without a glass substrate in the range of 350~1100 nm. Conversion cell efficiency of a-Si using ZnO TCO was comparable to or higher than the high cost SnO2:F TCO depending on the process condition..