Zinc oxide waveguide produced by thermal oxidation of chemical bath deposited zinc sulphide thin films

ZnO waveguiding layers deposited onto soda lime glass were produced from the thermal oxidation of ZnS thin films elaborated by a carefully conducted chemical bath deposition (CBD) method. X-ray diffraction indicated that ZnO films possessing a polycrystalline hexagonal structure were obtained. M-line spectroscopy was used to determine the refractive index and the thickness of ZnO films which were 1.90 at wavelength λ=632.8 and 130 nm, respectively. These analyses were also conducted on the ZnS elaborated films before annealing treatment. The ZnO films presented waveguiding properties and optical losses of 3.0±0.5 dB cm−1 at λ=632.8 nm were measured. The waveguide Raman spectrum of the ZnO films mainly exhibited a broad band at 558 cm−1 which corresponds to longitudinal optical phonon and a large band which is assigned to amorphous ZnO material.