The window layers effect on the hardness improvement of space solar cells exposed to the 1 MeV electron irradiations

Because of their state of art technology, GaAs solar cellsare generally preferred for spatial applications. Exposure to proton and electron irradiations, solar cellssuffer significant degradation in their performance such as short circuit current and open circuit voltage. Adding a window layer helps in effectively reducing the surface recombination at the emitter surface of the solar cellwithout absorbing the useful light required for the device. It remains to study the physics of the window-emitter hetero-interface in order to understand how the window layer presence increases the minority carrier lifetimeof the solar cellexposed to particles irradiation. In this work Numerical simulation has been used to study the AlxGa1- xAs window composition effect on the current-voltage characteristicsof a GaAs solar cellunder AM0 illumination and exposed to 1 MeV electron irradiation. To predict the effect of window layers on solar cellsdegradation, the current voltage characteristicare evaluated for different electron irradiation fluences. The findings are supported by experimental data. They lead us to get to know how the window layer improves resistance to electron irradiation through its own parameters.