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We report on the potentiality of the MAPLE technique for the deposition of thin films of colloidal nanoparticles and organic materials to be used for gas sensors based on electrical and optical transduction mechanisms. The MAPLE technique seems very promising, since it permits a good thickness control even on rough substrates, generally used to enhance the active surface for gas adsorption.TiO2 and SnO2 (with a capping layer of trioctylphosphine) colloidal nanoparticles were diluted in suitable solvents (0.2% concentration), frozen in liquid nitrogen and irradiated with ArF or KrF excimer lasers. The nanoparticle thin films were deposited on silica, interdigitated alumina and< 100> Si substrates and submitted to morphological (SEMFEG), structural (XRD and FTIR), optical (UV-Vis transmission and photoluminescence) and electrical (sensing tests) characterizations. A uniform distribution of TiO2 nanoparticles, with an average size of∼ 10 nm, was obtained on flat and rough substrates. The TiO2 nanoparticles preserved the anatase crystalline structure, as evidenced by the XRD spectra. FTIR analysis showed that the SnO2 nanoparticles maintained the capping layer after the laser-assisted transfer process. This protective layer was removed after annealing at 400 0 C, the usual operating temperature of the sensor. Electrical tests performed in controlled atmosphere in presence of ethanol and acetone vapors evidenced a high value of the sensor response even at very low concentrations (20-200 ppm in dry air) of both vapors. As regards the preparation of organic based thin films, Methoxy Ge Triphenylcorrole (Ge-TPC-OCH3) was synthetised …
Publication date: 
25 Jun 2007

AP Caricato, A Luches, M Martino, F Romano, T Tunno, D Valerini, S Capone, J Spadavecchia, M Epifani, L Francioso, M Lomascolo, P Siciliano, R Rella, R Paolesse, M Mastroianni, F Mandoj

Biblio References: 
Pages: 70
“Fundamentals of Laser Assisted Micro–and Nanotechnologies”(FLAMN-07)