Project Going On In Matsumura Laboratory:
NEDO Solar Cell Project, “Low Cost Fabrication of High Efficiency Solar Cells by Cat-CVD Technology”
(2015 May to 2018 March, & 2018 April to 2020 March)

Purpose and Summary of Project

　Among various solar cells, crystalline silicon (c-Si) solar cells are the most promising and successful cells in the world market at present and even for 10 to 20 years future. Thus, it is very much valuable to develop a new technology fabricating high efficiency low cost c-Si solar cells for reducing the price of electricity price made by solar cells down to 7 yen/kWh, which is the cost commonly accepted for the conventional power generation.
　The purpose of the present research project is to develop the fabrication technology for amorphous-silicon (a-Si)/c-Si hetero-junction back contact (HBC) solar cells, by adapting a new thin film technology, Cat-CVD (Catalytic Chemical Vapor Deposition) technology, by which high quality thin films are prepared without plasma damages on the surface, and also by adapting a new low temperature impurity doping technology, Cat-doping (Catalytically cracked impurity Doping), in which phosphorus (P) or boron (B) atoms can be doped into c-Si at temperatures as low as 80℃ by using cracked species of phosphine (PH3) or diborane (B2H6).
　In the project, two research themes are set:
(Research Thema-1) Preparation of super high quality passivation films by Cat-CVD and fundamental study on mass production system for realizing it,
(Research Thema-2) Further improvement of quality of passivation, electrodes and other surface effects by Cat-doping and development of mass-production system realizing them.

　The target of the present project is to realize a-Si/-Si hetero-junction solar cells with the efficiency of 26% and to find the way that c-Si solar cells with 26% efficiency can be realized in mass-production under the strong tie with solar cell producing companies.