Phase Composition and Optical Properties of Fe-Doped Aluminum Oxynitride

This paper presents results on the synthesis, phase composition, and optical properties of Al₅O₆N aluminum oxynitride doped with Fe ions in a broad concentration range: from 0.01 to 5.0 at % (relative to aluminum). All of the samples, prepared by firing mixtures of Al₂O₃, AlN, and Fe₂O₃ at a temperature of 1750°C in flowing nitrogen, consisted of almost phase-pure γ-AlON, with small amounts of aluminum nitride and unidentified phases. The band gap E_g of AlON:Fe depends on Fe concentration and ranges from 5.76 to 5.88 eV. We have identified AlON:Fe luminescence due to native defects and extrinsic emission centers and measured the luminescence intensity of emission bands as a function of Fe concentration in AlON. The presence of Fe in AlON leads to an increase in optical absorption and a decrease in intrinsic luminescence intensity in the material.