Minority carrier injection-enhanced recovery of radiation-induced defects in p-InGaP and solar cells

The first direct recombination enhanced annealing of the radiation-induced defect H2 in p-InGaP has been observed by deep level transient spectroscopy (DLTS). Detailed analysis shows that the main defect H2 (Ev+0.50 eV) in p-InGaP exhibits minority-carrier injection-enhanced annealing characterized by an activation energy (ΔE=0.51 eV) close to the activation energy for the recovery (ΔE=0.54 eV) of the defect responsible for diffusion length degradation in n⁺-p solar cells. Double pulse DLTS experiments reveal that hole trap H2 has large minority carrier capture cross section and apparently acts as a recombination center. We were able to show that the mechanism involved in minority carrier injection annealing of the H2 defect is an energy release mechanism