As an adhesion layer between Au nanoparticles (NPs) and a SiO 2/Si(100) substrate, a TiO2 film was formed on SiO 2/Si(100) by Ti deposition in O2 at 1×10 -6 Torr with a slow deposition rate (0.16nm/min). The Ti 2p core-level spectra were measured for the film, and only peaks from the Ti atoms in the oxidation state of 4+ were observed, indicating that the TiO2 film was highly stoichiometric. An atomic force microscopy (AFM) study showed that the surface roughness (rms) of the film was about 0.3 nm. Au NPs with a diameter of 10nm were deposited on the film surface by a dip-coating method. Scanning electron microscopy (SEM) images showed that some of the NPs are fused with each other to form merged particles. The Au 4f spectra consisted mostly of peaks from metallic Au, suggesting that NPs are chemically stable on a TiO 2 film.