Combined infrared and Raman study of the optical phonons of defect chalcopyrite single crystals

Abstract Infrared and Raman investigations of CdAl 2 Se 4 , ZnAl 2 Se 4 and ZnIn 2 Se 4 single crystals with respect to the optical phonon mode activities predicted for space groups I 4 and I 4 2 m are reported. Variations of the cation and vacancy distributions affect the infrared reflectivity spectra more pronounced than the Raman spectra of the compounds. To decide whether the compounds crystallize in space group I 4 or I 4 2 m by means of optical spectroscopy both infrared as well as Raman spectroscopy have to be used.