Single-source CVD of zinc sulfide-based thin films from zinc bis(O-ethykanthate)

A novel single-source precursor, zinc bis(O-ethylxanthate), was employed for the CVD of ZnS-based thin films. The coatings were deposited on SiO2 and SiO2/Si(100) substrates in a N-2 atmosphere in a cold-wall reactor in the temperature range 250-400 degreesC. The optical properties of the films were investigated by ultra violet-visible (UV-vis) absorption and Fourier transform infrared (FTIR) spectroscopies. The surface and in-depth chemical composition were studied by X-ray photoelectron spectroscopy (XPS), X-ray excited Auger electron spectroscopy (XE-AES), and secondary ion mass spectrometry (SIMS). Finally, atomic force microscopy (AFM) was employed to analyze the surface morphology of the coatings. Very thin films, with thickness less than 30 nm and no evidence of crystalline phases, were grown at temperatures of at least 300 degreesC. Optical measurement showed that the coatings were highly transparent ( > 80 %) throughout the visible and IR spectral ranges.