Energy levels of native defects in zinc germanium diphosphide

Abstract

Electron paramagnetic resonance (EPR) and photo-EPR investigations of as-grown, post-growth annealed and electron irradiated zinc germanium diphosphide (ZnGeP 2) crystals allowed the determination of native acceptor- and donor-related defect levels in the ZnGeP 2 bandgap. From the photoinduced generation of the V Zn − EPR spectrum for electron-irradiated samples with the Fermi-level above the recharging level it is inferred that the V Zn −−/− acceptor state is located at 1.02±0.03 eV below the conduction band. Observation of the recharging process in as-grown and post-growth annealed samples yields the localization of the Ge anti-site donor level Ge Zn +/++ at E opt= E V+1.70±0.03 eV. Moreover, photoinduced processes involving the quenching and generation of the V Zn − and V P 0 EPR spectra, respectively, are observed with an energy of E opt=0.64±0.03 eV. A model that can explain the complementary changes of the V Zn − and V P 0 EPR intensities is briefly discussed.