SnO2 nanostructured films obtained by pulsed laser ablation deposition

Nanostructured tin oxide films were deposited on Si(1 0 0) substrates at room temperature using the PLAD method. Depositions were achieved by using a XeCl* laser, with a fluence of 10 J/cm2 to ablate a SnO2 target either in vacuum or in an atmosphere containing a relatively low partial pressure (10 2 to 100 Pa) of O2. A range of spectroscopic diffraction and real space imaging techniques, SEM, EDS, XRD, and XPS were used in order to characterize the surface morphology, structure, and composition of films. XPS results indicate that the film deposited in vacuum comprises a mixture of Sn, SnO and SnO2. In contrast, films deposited in oxygen comprise only SnO and SnO2. This indicates that the deposition of tin oxide films in relatively low partial pressures of O2 prevents the accumulation of unreacted tin metal within the resulting film. SEM studies reveal a sub-micron grain size structure, while XRD analyses indicate that the samples are crystalline, with no evidence for the presence of amorphous material. In this paper we discuss the significance and implications of these findings in terms of the optimization of tin oxide films for use in gas sensing devices and other technological applications.