Hetero-epitaxy of perovskite oxides on GaAs ( 001 ) by molecular beam epitaxy

Hetero-epitaxy of single-crystal perovskite SrTiO 3 on GaAs ( 001 ) was achieved using molecular beam epitaxy. The growth was accomplished by deposition of a submonolayer of titanium on GaAs ( 001 ) , followed by the co-deposition of strontium and titanium initiated at a low-temperature, low-oxygen-pressure condition. X-ray photoelectron spectroscopy showed that the Ti prelayer reacted with As and formed TiAs -like species on the As terminated GaAs ( 001 ) surface. Reflection-high-energy-electron diffraction showed that SrTiO 3 grew coherently on the GaAs ( 001 ) at early stage of growth. This coherent behavior began to degrade when SrTiO 3 thickness exceeded 20 Å . Cross-sectional transmission electron microscopy revealed an abrupt interface between SrTiO 3 and GaAs and good crystallinity of the SrTiO 3 film. An epitaxial relationship between SrTiO 3 and GaAs was further confirmed by x-ray diffraction. The success of growth of SrTiO 3 on GaAs paves the way for integration of various functional perovskite oxides with GaAs .