R&D activities of crystalline silicon solar cells in Japan

Research and development of crystalline silicon solar cells in Japan have greatly advanced for the past 10 years. Fundamental research has been conducted on the recombination and passivation of minority carriers at Si/SiO2 interfaces and in bulk regions including grain boundaries. Qualities of Si feedstock and substrates have been improved. A small area cell efficiency using monocrystalline silicon substrates has reached 21% and that for large-area, multicrystalline solar cells up to 17% by using low-cost cell fabrication processes. Such high efficiency values are realized by tenacious improvement of substrate quality and the development of new processes for fabricating solar cells.