Germanium Growth Orientation on SrTiO3 (001) 2 × 1 Surface: Role of Surface Reduction

• Published in: Journal of physical chemistry. C 2013-05, Vol.117 (19), p.9887-9894
• Main Authors: Wang, Junjie, Lefebvre, Isabelle
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Electron states; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic structure of nanoscale materials : clusters, nanoparticles, nanotubes, and nanocrystals; Exact sciences and technology; Materials science; Methods of crystal growth; physics of crystal growth; Methods of electronic structure calculations; Physics; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp4013976

We present a theoretical study of germanium growth orientation dependence on SrTiO3 surface structure using first-principles calculations. Contrary to much work on the SrTiO3 surface which considers the simple TiO2 termination, we work on the now well known 2 × 1 reconstructed surface, which is terminated with a TiO2 double layer. We study the oxygen reduction at this surface maintaining the 2 × 1 reconstruction. Analysis of its electronic structure shows that the reduction leads to a metallic surface and changes of the surface bond characteristics. Therefore, the growth routes for Ge epitaxy are studied. It is demonstrated that the reduction favors the creation of the Ge–O bonds by weakening the strength of the Ti–O bonds. It gives the possibility of Ge[001] growth direction, which is not possible on a nonreduced surface.