Crystal-Field Spectra of3dnImpurities in II-VI and III-V Compound Semiconductors

Abstract

The spectra of $\mathrm{Fe}\left(d^6\right)$ in ZnSe, ZnTe, CdS, CdTe, GaP, and GaAs, and of $\mathrm{Co}\left(d^7\right)$ in ZnSe, ZnTe, CdTe, GaP, and GaAs, are presented. It is found that a crystal-field description is useful even in such covalent materials. The crystal-field splitting $\Delta$ depends on the impurity, but for a given impurity, $\Delta$ varies by less than 25% through the II-VI series. The Racah parameter $B$ is strongly dependent on the host crystal and can decrease to less than a third of the free-ion value. From plots of the variation of $B$ and $\Delta$ with properties of the impurity or host crystal, the spectra of hitherto unexplored systems may be predicted.