Theoretical investigations of the optical spectra and EPR parameters for Yb3+ ions in GaN epilayer

In this paper, the crystal-field energy levels of Yb3+ in GaN epilayer are calculated using crystal-field theory. The perfect agreement between measured and calculated energy values obtained, under C3v point symmetry assumption, allows us to conclude that we deal with an isolated Yb3+ ion in the GaN lattice. The crystal field parameters of Yb3+ ions in this host are calculated and compared to those obtained for Yb3+ in CaF2 in C3v symmetry site. The respective strength crystal field parameter permits to calculate the maximum splitting of the 2F7/2 ground state, which is in good agreement with the observed value. The 2F5/2 missing experimental energy level is calculated and the predicted emissions from this level are calculated and can be attributed in the emission spectra.The lowest Kramer's doublets are found to be E1/2 for Yb3+ ion in trigonal symmetry site. The EPR g factors g// and g⊥ and hyperfine structure constants A// and A⊥ are investigated using the perturbation formulas. The admixture of different states is induced.