Effect of reactive gas flow on structural and optical properties of sputtered silver oxide thin films; Kramers-Kronig method.

Silver oxide nano layers were deposited on SiO2 ‎amorphous substrates by RF reactive magnetron of a silver target (99.999%) in different oxygen gas flow (1, 2 to 3 SCCM) in Ar–O2 reactive gas mixtures. Their crystallography, phase transitions and nanostructures were investigated by X-ray diffraction, SEM, EDAX and AFM analysis. Optical properties ‎were calculated using Kramers-Kronig relations by reflectance spectra. According to X-ray diffraction measurements, at low oxygen flow rate, in addition to cubic phase of Ag, Ag2O phase of silver oxide was observed while, at higher oxygen flow rate only Ag2O crystalline phase was occurred. However, by increasing the oxygen flow to 3 SCCM, target poisoning happened and deposition rate decreased. The SEM images showed that by increasing oxygen flow, dense texture with non-homogenous grains changed to porous morphology. Optical results revealed that the highest optical band gap of 2.7 eV was achieved at highest oxygen flow (3 SCCM) and the highest transmittance of ~ 60% was obtained at same flow. [ABSTRACT FROM AUTHOR]