ATOMIC CONTROL OF SRTIO3 SURFACE FOR PERFECT EPITAXY OF PEROVSKITE OXIDES

Atomically smooth SrTiO3(100) surface having one unit cell high steps and atomically flat terraces was obtained by selective etching of SrO atomic layer in a NH4F-HF solution. Carbon contamination on the as-etc hed surface could be removed by annealing above 600 degrees C in UHV, as verified by Auger electron spectroscopy and low energy electron dif fraction. Atomically flat terraces corrugated with a spacing of 0.4 nm was observed by scanning tunneling microscopy. The intensity oscillat ion of reflection high energy electron diffraction was continuously ob served during the homoepitaxy on the surface by laser molecular beam e pitaxy, proving the requisite of this wet-treated substrate for the pe rfect epitaxy of perovskite oxides.