Nanocrystallized SnO2 thin films deposited on Si and LaAlO3 substrates by pulsed-MOCVD technique for electrochemical applications

Tin dioxide (SnO2) thin films are deposited by pulsed metalorganic chemical vapor deposition (pulsed-MOCVD) on Si and LaAlO3 substrates from tin precursor (Sn(thd)2). The effects of two synthesis parameters on the structural and electrical properties of the films are studied. The structural modifications are assessed by grazing incidence X-ray diffraction (GIXRD) and Fourier transform infra-red spectroscopy (FT-IR). Two SnO2 structures are observed in the deposited thin films (tetragonal and orthorhombic) and various preferential orientations of these SnO2 structures are obtained according to the substrate temperature and the deposition frequency used. The morphology and the microstructure of the films are analyzed by field emission gun-scanning electron microscopy (FEG-SEM). The films are dense and well crystallized with various nanocrystalline morphologies. The electrical measurements carried out on the deposited SnO2 thin film show that the observed morphological and structural modifications induce changes of its electrical properties. Finally, the electrochemical grafting of an organic layer is carried out on the various deposited SnO2 surfaces to obtain new hybrid materials. Such innovative materials are very attractive as they have particular surface properties which make them powerful tools for thermoelectrical applications and for sensor applications for the detection of various ionic species at very low concentrations in aqueous media.