Theoretical investigations of the optical spectra and EPR parameters for Yb 3+ ions in GaN epilayer

Abstract

In this paper, the crystal-field energy levels of Yb 3+ in GaN epilayer are calculated using crystal-field theory. The perfect agreement between measured and calculated energy values obtained, under C 3v point symmetry assumption, allows us to conclude that we deal with an isolated Yb 3+ ion in the GaN lattice. The crystal field parameters of Yb 3+ ions in this host are calculated and compared to those obtained for Yb 3+ in CaF 2 in C 3v symmetry site. The respective strength crystal field parameter permits to calculate the maximum splitting of the 2F 7/2 ground state, which is in good agreement with the observed value. The 2F 5/2 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 E 1/2 for Yb 3+ 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.