This paper reports the survey results on analysis of super-high efficiency solar cells for practical use in fiscal 1994. (1) On the survey on crystalline compound solar cells, it was pointed out that the present study target is III-V compound semiconductor solar cell, and efficiencies of 36-39% are theoretically expected by use of two-junction cells. (2) On structure of super-high efficiency solar cells of 40%, selection of upper and lower cell materials for multi-junction cells, high-efficiency tandem Si solar cells, and the merit and possibility of light collection operation were surveyed, and their issues were discussed. (3) On physical properties of mixed crystalline semiconductors and characteristic evaluation of solar cells, impurities, trap center, minority carrier life, and applicability of supper lattice structure to high-efficiency solar cells were surveyed. (4) On fabrication technology of compound semiconductor solar cells, various problems of and approaches to electrode formation and antireflection film technologies, the meaning and issues of thin film substrate technology and continuous process, trial calculation of costs, safety, and resource problem were surveyed.
Tatsuta, M 
- New Energy and Industrial Technology Development Organization, Tokyo (Japan)