# LATTICE VIBRATIONS IN $CdS_{x}Se_{1-x}$ MIXED CRYSTALS.

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 Title: LATTICE VIBRATIONS IN $CdS_{x}Se_{1-x}$ MIXED CRYSTALS. Creators: Parrish, J. F.; Perry, C. H.; Brafman, O.; Mitra, S. S. Issue Date: 1967 Publisher: Ohio State University Abstract: The far infrared and Raman spectra of mixed crystals of CdS/CdSe have been measured. X-ray measurements indicate good quality mixed crystals with well defined lattice constants and no evidence of large scale clustering. Two distinct reststrahlen bands have been observed in the far infrared reflection spectrum and were analyzed with both Kramers-Kronig and damped oscillator models in order to extract the optically active TO mode frequencies. The LO frequencies were obtained from the Raman spectra. The TO mode associated with the CdS increase in frequency and the corresponding LO mode decreases in frequency as the concentration of CdSe increases. The two frequencies merge near 100% CdSe predicting the frequency of the CdS local mode in CdSe. The frequencies of the TO and LO modes associated with the CdSe behave similarly. Transmittance measurements on thin crystals have yielded a consistent assignment for the two phonon combination bands and confirm the existence of the CdS local mode in CdSe. Description: This research is supported in part by Air Force Cambridge Research Laboratories under Contracts AF19(628)-6066 and AF19(628)-6042. The research of the Spectroscopy Laboratory is sponsored in part by the National Science Foundation Grant No. GP-4923. The work in Research Laboratory of Electronics is sponsored in part by the Joint Services Electronics Program (Contract DA28-043-AMC-02536(E)). The research of Brafman and Mitra is supported in part by the Advanced Research Projects Agency. Grant No. DA-ARO-D-31-124-G754. Present address of J. F. Parrish: N.A.S.A., Electronics Research Center, Cambridge, Mass. Author Institution: Spectroscopy Laboratory and Research Laboratory of Electronics, Massachusetts Institute of Technology; Department of Electrical Engineering, University of Rhode Island URI: http://hdl.handle.net/1811/15293 Other Identifiers: 1967-N-7