Highly epitaxial and pure(001)-oriented CeO2films were grown on SrTiO3(001)substrates by laser molecular beam epitaxy method without any gas ambient.Layer-by-layer epitaxial growth mode of CeO2was confirmed by in situ reflection high-energy electron diffraction(RHEED)observations.High-resolution X-ray diffraction(HRXRD)and high-resolution transmission electron microscopy(HRTEM)results indicated the STO(100)//CeO2(100),STO[100]//CeO2[110]epitaxial relationship for out-of-plane and in-plane,respectively.The formation mechanism of the epitaxial film was also discussed in the light of a theoretical model.Chemical states of the LMBE ceria films were evaluated and evidences for the existence of Ce3+and oxygen vacancies were presented.
