Matrix Assisted Pulsed Laser Evaporation for TiO2 nanoparticle thin film deposition

The Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique has been used, for the first time, for the successful deposition of titania (TiO2) nanostructured thin films. An aqueous solution (20% wt) of colloidal TiO2 nanoparticles with anatase phase, synthesized by a novel chemical route, was frozen and then irradiated with a pulsed ArF excimer laser (?=193 nm, ?=20 ns). The nanoparticles were deposited on (100) Si substrates. A uniform and compact distribution of TiO2 nanoparticles forming a continuous film was obtained, as demonstrated by high resolution Scanning Electron Microscopy (SEM-FEG) inspection. Randomly distributed spherical particles with an average diameter of 200 nm were also observed on the film. A comparison with a spin coated thin film obtained from the same starting solution allowed to better evaluate the effects of the laser deposition process. Energy Dispersive X-ray Spectroscopy (EDX) revealed the presence of only the titanium and oxygen signals, and X-Ray Diffraction (XRD) spectra demonstrated that the anatase phase and nanoparticle dimensions were preserved. Our results are very interesting for the development of technological devices like sensors.