Physical model of the infrared dielectric function of zinc sulfide

Abstract

We apply the Gaussian-oscillator model of the infrared dielectric function of ZnS materials prepared by hot pressing (HP) and chemical vapor deposition (CVD). Chemical factor analysis of the 700 to 1300 cm−1 spectral range shows 3 oscillators in the HP material and 4 in that prepared by CVD. The origin of these oscillators is identified. In both materials, high-order transverse-optical (TO) and longitudinal-acoustic (LA) vibration modes are excited. In HP-ZnS, the four oscillators are related to the 3TO, 1TO + 2LA, 3LA, and 4LA modes. Only the first three are found in the CVD material. These results clarify the physical mechanisms of lattice absorption of ZnS in this spectral range.