Super-high efficiency solar cell R&D program in Japan

The R&D program of super-high efficiency solar cells, especially III-V compound semiconductor solar cells, in the New Sunshine Project of MITI (Ministry of International Trade and Industry) in Japan is described. In order to use III-V compound solar cells widely, it is necessary to improve their conversion efficiency and reduce their cost. Based on the above background, the Japanese R&D program of super-high efficiency solar cells started in FY (fiscal year) 1990 with support from MITI and NEDO. Up to now, InGaP/GaAs two-junction solar cells have reached the highest efficiency achieved in Japan of over 30%. By the end of the FY 1996, the authors hope an efficiency of 35% will be achieved.