Optical Phonons in ZnGeP₂ and CdGeP₂

Abstract

Abstract The phonon spectra of ZnGeP 2 and CdGeP 2 , determined by Raman scattering on single crystals at room and liquid nitrogen temperature, are presented. The close coincidence of the zone center phonon energies of ZnGeP 2 with the corresponding τ, X, and W modes of its isoelectronic analogue, GaP, bears out the expected similarity of lattice vibrations in ternary chalcopyrite compounds and binary zincblende materials. Differences between ZnGeP, and CdGeP 2 can be attributed to mass and force constant differences when Zn is substituted by the heavier Cd atom.