Linear electroabsorption due to substitutional deep impurities in wurtzite‐type crystals: II. Experimental study of Co 2+ in CdS and CdSe

Measurements are made of linear electroabsorption spectra in the range of the 4 A 2 → 4 T 1 ( 4 F) and 4 A 2 → 4 T 1 ( 4 P) absorption bands of substitutional Co 2+ in CdS and CdSe crystals for electric fields parallel and perpendicular to the hexagonal c ‐axis, at 77 and 300 K. The observed dependences of these spectra on field and polarization direction can be completely explained on the basis of the theoretical treatment given in the first part of this work. A moment analysis is performed for CdS: Co 2+ , and this leads to values for the linear Stark splittings and field‐induced changes in transition probability. The axial crystalfield splittings of the T, excited levels of CdS: Co 2+ are also determined, and their similarity to the external field splittings for F ‖ c is emphasized.