Surface structure and electrochemical properties of platinum films grown on SrTiO3(100) substrates

• Published in: Surface science 2017-12, Vol.666, p.14-22
• Main Authors: Kasai, Masahiro, Dohi, Hideyuki
• Format: Article
• Language: English
• Subjects: Atomic force microscopy; Atomic structure; Catalyst; Chemical compounds; Diffraction patterns; Electrochemical analysis; Electron diffraction; Hetero-epitaxial films; Magnetron sputtering; Platinum; Polycrystals; Preferred orientation; Pt films; SrTiO3 substrate; Strontium titanates; Substrates; Surface structure; Temperature; Thin films; Twin boundaries
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2017.08.018

•Hetero-epitaxial growth of Pt on SrTiO3 was studied.•A two-dimensional polycrystal was observed at 400 °C.•Twin boundaries formed by Pt(100) and (110) domain was shown as V-shaped streaks.•An epitaxial film with atomically flat surface was obtained at 750 °C. We fabricated Pt films on SrTiO3 (STO)(100) using a DC-magnetron sputtering method to investigate the preferred orientation, surface structure, and electrochemical property. A film grown at 400 °C showed the two-dimensional polycrystalline features of Pt(111). Reflection high-energy electron diffraction (RHEED) showed diffraction patterns independent of the in-plane incident angle of the film. Films grown at 600 and 700 °C exhibited a preferred orientation of Pt(100) and (110). The films exhibited the morphology of faceted islands with roughness of several tens of nm, which consisted of two kinds of domains, namely a domain with preferred orientation of (100) and one with (110). The (100) and (110) domains had 45-degree twin boundaries, which were observed as V-shaped streaks by RHEED. The (100) domain was aligned in orientation of [011]Pt//[010]STO, which suggests that the binding strength of the (110) plane at the interface was larger than that of the (100). With a further increase in the growth temperature up to 750 °C, the film primarily showed a preferred orientation of (100) with an in-plane orientation of [010]Pt//[010]STO. The film also showed an island structure; however, atomic force microscopy revealed that the top was atomically flat. [Display omitted]