Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 51: Oxides and insulators: Epitaxy and growth
O 51.8: Vortrag
Mittwoch, 28. März 2012, 18:30–18:45, HE 101
Atomic-scale optimization of homoepitaxial growth of SrTiO3(110) thin film — •Zhiming Wang1,2, Lin Gu2, Yuan Yao2, Jiandong Guo2, Michael Schmid1, and Ulrike Diebold1 — 1Institut für Angewandte Physik, Technische Universität Wien, Wien 1040, Austria — 2Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Oxide multilayers display a rich diversity of properties that are different from their constituent materials. To understand the underlying physical mechanisms, it is essential to construct the oxide heterostructures with atomic-scale precision. We study homoepitaxial growth of SrTiO3(110) with oxide molecular beam epitaxy and use scanning tunneling microscopy and transmission electron microscopy for characterization of the films. The SrTiO3(110) surface exhibits a series of reconstructions, (n×1) and (m×8) (with n=4-6, m=2,6), which can be changed reversibly by deposition of Ti or Sr, These reconstructions are clearly observed by high energy electron diffraction at thin film growth temperature. This was used to optimize the Sr to Ti flux ratio in real time. We realized layer-by-layer growth of thin films with a deviation of cation stoichiometry of < 0.5% revealed by energy dispersive spectroscopy. The surface is always reconstructed and the buried layers transform into stochiometric SrTiO3 during growth. Films prefer to grow along [110] on (n×1) (n=4-6) surfaces, and along [001] on the (2×8) surface. This leads to the formation of nanoscale trenches on surfaces with mixed terminations. This work was supported by the Austrian Science Fund (FWF project F45).