Ellipsometry study of optical properties and dielectric response of SnS2 and GaS crystals.

In this paper, stannic sulfide(SnS₂) and gallium sulfide (GaS) crystals were grown by the chemical vapor transmission (CVT) method. Correlation analysis of X-ray diffraction, X-ray photoelectron spectroscopy and Raman vibrational modes of the two materials proved the high quality and purity of the sample growth. The absorption characteristics of the two materials were measured by spectrophotometer, and it was found that SnS₂ and GaS crystals had absorption peaks at 390 nm and 460 nm, respectively. The corresponding band gap was calculated by the Tauc diagram. In addition, the dielectric response and optical properties of SnS₂ and GaS crystal at wavelengths from 250 to 1000 nm were investigated by using ellipsometry and first-principles calculations. Similar broad and low absorption bands of both materials were found in the visible and infrared regions, and a high extinction coefficient was found in the ultraviolet region, which facilitates their use as corresponding photodetectors. These results are helpful for the study of the physical properties of SnS₂ and GaS crystals and their related applications. [ABSTRACT FROM AUTHOR]