Photoactivity of Chemically Deposited Rutile Thin Films on Si(111)

Chemical Bath Deposition from acidic (pH $<$ 2) solutions at low temperature (35$^{\circ}$C -- 55$^{\circ}$C) produced thin titanium dioxide films with rutile crystalline structure on clean Si(111) wafers. The films were characterized by X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), and X-ray Diffraction (XRD). Their thicknesses varied from 300 nm up to $\sim $ 1$\mu $m, and annealing was required to ensure adherence to the Si(111) substrate. SEM images show a rough TiO$_{2}$ surface, and XRD indicates the rutile structure of TiO$_{2}$. The rutile films exhibit photoactivity as evidenced by the decomposition of methyl orange when exposed to a 254 nm (4.88 eV) lamp.