Multi-phonon interaction of ZnS material based on two-dimensional correlation analysis

Zinc sulfide material is one of the important materials for infrared optical window in the long wavelength region. In this paper, the change of the spectral transmittance from room temperature to 600℃ was studied for the zinc sulfide materials prepared by chemical vapor deposition (CVD) and hot pressing (HP). Based on the two-dimensional correlation spectrum analysis technique, the interaction of the phonons in the long wave absorption region was obtained. In the long wave absorption band from 700 cm^-1 to 1 250 cm^-1, the phonon frequencies of CVD ZnS is the third harmonic frequencies in the transverse vibration mode (TO) and the third harmonic frequency in the longitudinal acoustic mode (LA). The phonon frequencies of HP ZnS are 3TO, 3LA and 4LA, and the response under temperature is 3LA, 3TO and 4LA in proper order. The vibration absorption of ZnS impurity prepared by the two techniques has an effect on the spectral transmittance in the range from 1250 cm^-1 to 2000 cm^-1 under the action of temperature, and the increase of the transmittance in different degrees occurs. Because of the difference of impurities, the transmittance of CVD ZnS is more significant than that of HP ZnS at high temperature environment.