Resonant optical spectroscopy of Er3+ centers in hexagonal GaN-analysis of symmetry

In this paper the site symmetry and site location of Er3+ ions in hexagonal GaN determined basing on high resolution resonant optical spectroscopy is reported. A single center is separated from the photoluminescence excitation spectra to the 4I11/2 state of Er3+ and the energy levels of this center were fitted in point charge approximation. From the values of crystal field parameters we conclude that Er occupies a substitutional lattice site in the crystal. This work is a continuation of our previous results for the 4I9/2 state.