Fabrication of zinc oxide, titanium oxide and organic entrapped silica Thin films via laser assisted molecular beam deposition

Thin films of zinc oxide, titanium oxide and nonlinear optical organic chromophores entrapped silica were all fabricated by using a new technique called laser assisted molecular beam deposition (LAMBD). In the cases of the zinc and titanium oxides, molecular oxygen was supersonically expanded into the laser ablated plasma plume of pure metallic targets and then directed towards a substrate. In the case of organic entrapped silica, a supersonic expansion of organic entrained in He canier gas was mixed with an expansion containing gas phase aggregates of silica, and then directed toward the substrate. The gas phase aggregates of silica were produced by a supersonic expansion of He canier gas into a laser ablated glass rod. Micron and submicron thick films were deposited on a variety of substrates which were situated in the path of the molecular beams. These films were then studied via scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and uv-visible spectroscopy. The quality of the oxide films were found to be largely dependent on the fluence of the incident laser, the expansion conditions employed and the metal target used. Comparing zinc and titanium, when ablated under identical experimental conditions, titanium produced the most homogeneous film. The binding energy of the Ti 2p_3/2 photoelectron peak and the splitting of the Ti 2p doublet indicate that the Ti in the deposited film is in the +4 oxidation state. The optical spectra of organic entrapped silica films, dissolved in chloroform, are identical to that of the pure organic compounds.