Effect of Sr adsorption on stability of and epitaxial SrTiO3 growth on Si(001) surface

The geometric and electronic structures of the Sr adsorbed Si(001) surface were investigated using photoemission spectroscopy, electron diffraction, scanning tunneling microscopy, and Rutherford backscattering spectrometry. Results showed that the Sr adsorbed Si(001) exhibited several reconstructions depending upon the Sr coverage. Photoemission results revealed that at one half mono-layer of Sr coverage the dimer-derived surface states disappeared and the stability of Si increased accordingly against oxidation at elevated temperatures. Using this Sr covered surface as a template, epitaxial SrTiO 3 films were grown on the vicinal Si(001) substrates using molecular beam epitaxy. The growth process is explained in terms of kinetically limited reaction facilitated by a local energy minimum induced by the Sr adsorption at Si(001) surface.