Extended X-ray absorption fine structure study of Er bonding in AlNO:Erx films with x <= 3.6%

The structural properties of Er-doped AlNO epilayers grown by radio frequency magnetron sputtering were studied by Extended X-ray Absorption Fine Structure spectra recorded at the Er L3 edge. The analysis revealed that Er substitutes for Al in all the studied samples, and the increase in the Er concentration from 0.5 to 3.6 at. % is not accompanied by the formation of ErN, Er2O3, or Er clusters. Simultaneously recorded X-ray Absorption Near Edge Structure spectra verify that the bonding configuration of Er is similar in all studied samples. The Er-N distance is constant at 2.18–2.19 A, i.e., approximately 15% larger than the Al-N bond length, revealing that the introduction of Er in the cation sublattice causes a considerable local distortion. The Debye-Waller factor, which measures the static disorder of the second nearest shell of Al neighbors, has a local minimum for the sample containing 1% Er that coincides with the highest photoluminescence efficiency of the sample set.The structural properties of Er-doped AlNO epilayers grown by radio frequency magnetron sputtering were studied by Extended X-ray Absorption Fine Structure spectra recorded at the Er L3 edge. The analysis revealed that Er substitutes for Al in all the studied samples, and the increase in the Er concentration from 0.5 to 3.6 at. % is not accompanied by the formation of ErN, Er2O3, or Er clusters. Simultaneously recorded X-ray Absorption Near Edge Structure spectra verify that the bonding configuration of Er is similar in all studied samples. The Er-N distance is constant at 2.18–2.19 A, i.e., approximately 15% larger than the Al-N bond length, revealing that the introduction of Er in the cation sublattice causes a considerable local distortion. The Debye-Waller factor, which measures the static disorder of the second nearest shell of Al neighbors, has a local minimum for the sample containing 1% Er that coincides with the highest photoluminescence efficiency of the sample set.