Raman Study of Phonon Processes in CdSx Se1-x Mixed Crystals

The lattice vibrations of mixed crystals have been intensively studied for several years. Based on the Raman and infrared experiments, two extreme types of behavior of the q=O phonons have been reported. The “one-mode type” describes the situation when a unique frequency varying continuously with concentration is observed in each composition for any allowed mode. In addition the mode strength remains practically constant. In the “two-mode type” two bands for each allowed optic mode are observed, with frequencies characteristic for the two end-member crystals. The mode strength is proportional to the fractional weight of the respective component.