Abstract: This work aims to study the effects of evaporation rate on refractive index, surface morphology and stress of ZnS films. Electron beam evaporation was used to prepare the ZnS films. Firstly, the film was deposited on K9 substrate and the transmittance curve was tested by spectrophotometer. The refractive index of the film was obtained by spectral inversion method and the surface morphology of the sample was characterized by atomic force microscope. The film was also deposited on PI substrate and the stress of the film was calculated by Stoney formula. With the increase of evaporation rate, the refractive index first increases and then decreases. At the wavelength of 2000 nm, the maximum refractive index was 2.21, and the minimum was 2.07. The higher the evaporation rate, the looser the surface structure of the film sample is. The films prepared at different evaporation rates all show compressive stress. Increasing the evaporation rate can significantly reduce the stress of films. The performance of ZnS film was significantly affected by the evaporation rate. When the rate was 1.5 nm/s, the refractive index can reach the maximum value. When the rate was 2.5 nm/s, the stress can obtain the minimum value.

Key words: evaporation rate, ZnS, film, refractive index, stress