First-principles identification of defect levels in Er-doped GaN

Abstract

Erbium (Er) doped GaN has been studied extensively for optoelectronic applications, yet its defect physics is still not well understood. In this work, we report a first-principles hybrid density functional study of the structure, energetics, and thermodynamic transition levels of Er-related defect complexes in GaN. We discover for the first time that Er${}_{\mathrm{Ga}}$-C${}_{\mathrm{N}}$-$V_{\mathrm{N}}$, a defect complex of Er, a C impurity, and an N vacancy, and Er${}_{\mathrm{Ga}}$-O${}_{\mathrm{N}}$-$V_{\mathrm{N}}$, a complex of Er, an O impurity, and an N vacancy, form defect levels at 0.18 and 0.46 eV below the conduction band, respectively. Together with Er${}_{\mathrm{Ga}}$-$V_{\mathrm{N}}$, a defect complex of Er and an N vacancy which has recently been found to produce a donor level at 0.61 eV, these defect complexes provide explanation for the Er-related defect levels observed in experiments. The role of these defects in optical excitation of the luminescent Er center is also discussed.

arXiv comment4 pages, 3 figures

References in corpus (2)

• Electronic structure of rare-earth impurities in GaAs and GaN
• Hybrid density functional study of optically active Er${}^{3+}$ centers in GaN

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• Tuning the valence and concentration of europium and luminescence centers in GaN through co-doping and defect association
• Rare-earth defects in GaN: A systematic investigation of the lanthanide series