| Analysis of 1 MeV electron irradiation-induced defects in lattice mismatched n+/p- In 0.56Ga0.44P materials and solar cells and their correlation with solar cells parameters, using deep level transient spectroscopy (DLTS) technique are presented. The deep level spectra of metal organic vapor phase epitaxy (MOVPE)-grown lattice mismatched InGaP indicated three hole emitting traps H1 (0.50 eV), H2 (0.59 eV), H3 (0.63 eV), and two electron traps E1 (0.10 eV) and E2 (0.37 eV). Detailed study of minority-carrier injection, isothermal and isochronal annealing show the recovery of photovoltaic parameters in n+/p- In0.56Ga0.44P solar cells after 1MeV electron irradiation. Correlation of the solar cells characteristics with changes in the deep level transient Spectroscopy data observed in irradiated and annealed n +/p- InGaP diodes and solar cells shows that H1, H2, and H3 defects have dominant roles in governing the minority-carrier lifetime as well as carrier removal in the base layer. |
