GAAS Solar Cells on Si Wafers for Space Application

This paper describes the activities carried out to develop III-V compound solar cells on silicon-germanium substrates and presents the results achieved on large area GaAs/Ge/Si cells and on InGaP/InGaAs/Ge/Si dual and triple junction cells. The aim is to investigate the limits of this technology and the possible utilisation of these type of cells for terrestrial and space application. For both applications the main objective is to reduce the solar cell cost by replacing the expensive Ge substrates with a low cost Si substrate. Moreover, in space environment, GaAs/Si cells show a good tolerance to electrons irradiation and are lighter then standard GaAs cells