Growth and Characterization of Zinc Sulfide Thin Films Deposited by the Successive Ionic Layer Adsorption and Reaction (Silar) Method Using Complexed Zinc Ions As the Cation Precursor

Abstract

Zinc sulfide thin films were grown by the successive ionic layer adsorption and reaction method on soda lime glass and on indium tin oxide covered glass, using diluted solutions of ZnCl 2 complexed with triethanolamine (TEA) or ethylenediamine as the cation precursor and a diluted solution of Na 2S as the anion precursor. The growth rate of the ZnS film varied between 0.13 and 0.27 nm/cycle. The refractive indices were from 1.95 to 2.23, and the packing densities were from 72 to 90%. The highest refractive indices and packing densities were found in films grown on indium tin oxide with TEA-complexed zinc chloride as the cation precursor. The Zn:S ratio in the films was from 0.89 to 1.08. According to the X-ray diffraction study, the films were polycrystalline and presumably cubic. The EXAFS studies revealed that the crystallinity of the thin film deposited with TEA-complexed ZnCl 2 was similar to that of the films deposited with ZnCl 2 as the precursor. Annealing slightly improved the quality of the successive ionic layer adsorption and reaction grown ZnS films.