Structural, morphological, and optical properties of AgxO thin films deposited via obliquely angle deposition

This work reports on the optical, structural, and morphological properties of silver oxide thin films obtained by post-oxidation of silver deposited previously by the thermal evaporation technique. The samples were deposited on glass substrates using the oblique angle deposition technique for different angles of incidence ? (?=0 degrees, 20 degrees, 40 degrees, 60 degrees, 75 degrees, and 85 degrees). ? is defined as the angle between the particle flux and the normal to the substrate. The resulting thin films were annealed in the free air at two temperatures (300 degrees C and 400 degrees C). X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-visible-NIR spectrophotometer were performed to study the crystal structure, as well as the morphological and optical properties (transmittance and reflectance), of the AgxO samples. X-ray diffraction analysis revealed the presence of the AgxO phase for the silver films deposited at a high angle of incidence and for the annealing temperature 300 degrees C. In contrast, the diffractograms of the silver films annealed at 400 degrees C show an amorphous behavior. Optical results indicated that the direct band gap energy increases pursuant to increasing the angle of incidence ?. The absorption coefficients of AgxO thin films were found to be in the range of 10(3)-10(5) cm(-1). Additionally, we determined the birefringence for the layers annealed at 400 degrees C and found that the highest value of birefringence is obtained corresponding to the angle of incidence 60 degrees. Morphological analysis indicated that the porosity increases with the angle of incidence and highlights the amorphous nature of the films, which is attributed to the columnar structure.