Atomic and Electronic Structure of SrTiO$_{3}$/GaAs Hetero-Interfaces

Metal-oxide semiconductor interfaces have received much attention in recent years due to their potential applications in metal-oxide-semiconductor field-effect transistors. In this study we examine the atomic and electronic structures of epitaxial SrTiO$_{3}$[100] thin films on GaAs[001] using atomic-resolution Z-contrast imaging and electron energy loss spectroscopy in combination with first principles calculations to develop a fundamental understanding of the interfacial structure-property relationships. We will demonstrate that it is energetically favorable for SrO layer of SrTiO$_{3}$ to be in direct contact with the terminating As layer of GaAs, as opposed to the TiO$_{2}$ layer. However, the model with the simplest 1x1 surface unit cell is not in agreement with the photoemission data.$^{2}$ First principles total energy calculations will be used to consider how different GaAs(001) surface reconstructions are modified in the presence of SrTiO$_{3}$ to find the low-energy semiconducting interface. $^{2}$Y. Liang et al., \textit{Appl. Phys. Lett.,} \textbf{86} (8), 082905 (2005).