Development of Ultrathin Silicon and Gallium Arsenide Solar Cell for Space Application

The ultrathin silicon (Si) solar cell and gallium arsenide (Ga As) solar cell for increasing radiation resistance and improving power to mass ratio and improving high energy conversion efficiency, have been developed from 1982. NASDA has almost completed fundemental evaluation of these solar cells and got prospect for space applications. The ultrathin 50¿m Si solar cell with maximum efficiency 13.9% (average 13.2%) at Air Mass Zero (AMO) [135.3mW/cm² illumination and at 28°C] and the remaining Isc ratio of 82% after irradiation of lMeV electron fluences of 1 × 10¹⁵ e/cm² have been demonstrated. While, the GaAs solar cell consists of P-AlGaAs/P-GaAs/n-GaAs and have the maximum efficiency of 19.2% (average 17.5%) at AMO and the remaining Isc ratio of 87% after irradiation of lMeV electron fluences of 1 × 10¹⁵ e/cm².