Inuence of substrate heat treatment to the structural properties of ND:YAG thin films produced by femtosecond pulsed laser deposition

Abstract

The crystallinity, surface morphology and topography of the femtosecond pulsed laser deposited Nd:YAG film under in-situ and post deposition heat treatment were examined. Heat treatment improved the crystallinity of the film with the increase in the reflecting planes shown in X-ray diffraction data. Scanning electron micrograph of the heat treated film surface indicates a small degree of melting. Surface topography of the as-deposited Nd:YAG film under AFM shows size variation to within few tens of nanometers indicating the generation of nanoparticles. Temperature dependence of the cross section area, height and surface roughness of the film was determined and explained by the volume free energy of the film. Our results demonstrate the novel use of femtosecond laser to ablate and deposit laser crystal as well as heat treatment to engineer the structural properties of the film.