LATTICE VIBRATION-SPECTRA OF HG1-XZNXTE ALLOYS

Far infrared reflection spectra of Hg1-xZnxTe with x = 0 to 1 have been measured at 295 K in the spectral region 40 to 500 cm-1. The spectra exhibited two transverse optical phonon modes characteristic of II-VI mixed crystals. For x < 0.4 an additional phonon mode was observed at 96 cm-1. The spectra were analyzed by Kramers-Kronig integrations and by fitting them with a dynamic dielectric function. Random element isodisplacement (REI) model calculations of the dependence of the long-wavelength optic phonon frequencies on composition agreed well with experimental results. The REI model calculations were compared with previous results on HgCdTe and suggest a stronger HgTe force constant exists in HgZnTe than in HgCdTe. © 1990.