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, 1 MeV electrons and gamma-rays from a Co/sup 60/ source have been studied. The recombination component of the photovoltaic p/sup +/-n junctions yields the carrier lifetimes in the SCR /spl tau//sub w/ = (10/sup -10//spl divide/10/sup -8/)s. Estimates of the damage coefficient in the SCR - K/sub /spl tau/w/ 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.