Surface roughness reduction in Atomic Layer Epitaxy growth of titanium dioxide thin films

The surface smoothness of TiO2 films grown by atomic layer epitaxy was improved by incorporating thin intermediate Al2O3 layers into them. The elimination of light scattering from the film surface caused a marked increase in the specular transmittance. Optical measurements, atomic force microscopy, scanning electron microscopy and X-ray diffraction were used in examining the relationships between the amount of Al2O3 added and the optical, morphological and structural properties of the films. The mechanism of the surface roughness reduction is discussed.