Defect distribution in InGaAsN/GaAs multilayer solar cells

•DLTFS experiments were realized to study InGaAsN solar cells.•Traces of oxygen – arsenic vacancies, nitrogen interstitial complexes were stated.•Multi level separation method showed probable presence of nickel.•Most commonly described arsenic antisite defect EL2 was also observed.•Strongest response was associated with nitrogen split interstititals on a As site. Deep Level Transient Fourier Spectroscopy (DLTFS) experiments were realized to study emission and capture processes in InGaAsN multilayer solar cells grown on GaAs substrates by Atmospheric Pressure Metal Organic Vapor Phase Epitaxy (APMOVPE). As a referent structure for comparison purposes a basic GaAs p–n sample grown in the same system was also utilized. All the structures exhibited variety of deep energy levels with high concentrations. In addition to the most commonly described arsenic antisite defect, with activation energies 0.73–0.78eV, possible traces of oxygen–arsenic vacancies with 0.52eV and nitrogen interstitial complexes were evaluated. Most dominant electron trap at about 0.53eV below the conduction band EC was observed at different measurement conditions. Based on various references, this electron trap can be associated with a split interstitial defect containing two nitrogen atoms on the same As lattice site. Calculated energies and possible origins of these results were confirmed by Arrhenius curve comparison.