ИСТИНА

A comparative analysis of the efficiency of different approaches of low-temperature metallization for the processing of ITO/Cz-Si based solar cells is performed in this work. Vacuum evaporation, screen printing and laminated grid techniques were applied. Moreover, two different approaches for the solar cell processing were used: (i) conventional diffused-emitter solar cells with ITO antireflection coating and (ii) heterojunction (HJ) solar cells which consist of ITO/a-Si:H/Si structure. It is found that in all cases of solar cell processing the vacuum evaporation and the laminated grid technique are the best methods for a low-temperature metallization to ITO conductive layer. Efficiencies above 16% were obtained for ITO/diffused emitter/Si (10x10 cm2) solar cells using the vacuum evaporation method. The lamination grid technique was successfully applied for ITO/diffused emitter Cz-Si based bifacial solar cells and efficiencies above 18% for 6.5x6.5 cm2 solar cells were obtained. It is found that the low-temperature screen printing method is less efficient and has to be optimized to make good enough contacts to ITO layer and to be able to compete with the vacuum evaporation or with the laminated grid technique. These last two metallization techniques can be used at present to process high efficiency Si based solar cells with ITO transparent front side electrode/antireflection coating instead of silicon nitride.