STM and STS investigations of Ce-doped TiO2 nanoparticles

Ce-doped titanium oxide nanoparticles were investigated in the paper. The surface structures of undoped and Ce-doped TiO2 nanoparticles were observed by scanning tunneling microscopy (STM). The experimental results of scanning tunneling spectroscopy (STS) show that the surface electronic structures of TiO2 nanoparticles are modified by introducing new electronic states in the surface band gap through cerium ion doping. The results are discussed in terms of the influence of doping concentration on the surface band gap of TiO2.