Determination of the ionization energy of nitrogen acceptors in zinc oxide using photoluminescence spectroscopy

Photoluminescence spectroscopy of nitrogen-related emissions in ZnO is used to establish the ionization energy of the substitutional nitrogen acceptor. The temperature dependence of the nitrogen-related electron-acceptor (e,A0) emission band has been monitored in as-grown single crystals of ZnO. Line shape analysis of this band is used to determine the acceptor ionization energy. The temperature dependence of the band gap for ZnO was included in our analysis and the low-temperature acceptor ionization energy for substitutional nitrogen at an oxygen site in ZnO was found to be EA=209±3 meV. Our line shape analysis indicates a small temperature-dependent decrease in EA for T>5 K.

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