The recombination and tunnel current in GaAs-based solar cells: Effect of radiation

The space charge (depletion) region of photovoltaic and tunnel p-n junctions, as appeared, give an essential contribution to the characteristics of multi-cascade solar cells and to their radiation tolerance. In the present work the mechanisms of current passage in GaAs p-n junctions and their evolution under irradiation with 6.78 MeV protons, 1MeV electrons and gamma-rays from a Co-60 source have been studied. The recombination component of the photovoltaic p(+)-n junctions yields the carrier lifetimes in the SCR tau(w) = (10(-10) divided by 10(-8))s. Estimates of the damage coefficient in the SCR - K-tauw based on an analysis of the dependence of the carrier lifetime in the SCR on the irradiation fluences demonstrated that the damage coefficient is fluence dependent.