SnO 2 nanostructured films obtained by pulsed laser ablation deposition

Abstract

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/cm 2 to ablate a SnO 2 target either in vacuum or in an atmosphere containing a relatively low partial pressure (10 −2 to 100 Pa) of O 2. 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 SnO 2. In contrast, films deposited in oxygen comprise only SnO and SnO 2. This indicates that the deposition of tin oxide films in relatively low partial pressures of O 2 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.