Majority- and minority-carrier deep level traps in proton-irradiated $n+/p$-InGaP space solar cells

We report the properties of observed defects in $n+/p$-InGaP solar cells created by irradiation of protons of different energies. Three majority (hole) and a minority-carrier traps, labeled respectively as HP1 $(Ev+0.90±0.05 eV),$ HP2 $(Ev+0.73±0.05 eV),$ H2 $(Ev+0.55 eV),$ and EP1 $(Ec−0.54 eV),$ were identified using deep level transient spectroscopy. All majority-carrier traps were found to act as recombination centers. While the H2 trap present in the proton-irradiated $p$-InGaP was found to anneal out by minority-carrier injection, the other traps were not.