Shallow-homojunction GaAs cells with high resistance to 1-MeV electron radiation

We have recently reported the fabrication of single-crystal GaAs shallow-homojunction solar cells that have conversion efficiencies of about 20% at AM1 (17% at AM0). These cells employ an n+/p/p+ structure, prepared by chemical vapor deposition on either GaAs or Ge substrates. We have now demonstrated the superior resistance of such cells to 1-MeV electron radiation, which produces effects approximating those due to space radiation. The experiments were done on four cells at fluences up to 1016 e/cm2. One of the cells was found to have both higher initial and final maximum power per unit area than any space cells previously reported.