Epitaxial Growth of LaB6 Thin Films on Ultrasmooth Sapphire Substrate with Epitaxial SrB6 Buffer Layer

摘要

We fabricated epitaxial LaB6 (100) thin films on ultrasmooth sapphire (α-Al2O3 single crystal) (0001) substrate with epitaxial SrB6 buffer layer by laser molecular beam epitaxy. Reflection high-energy electron diffraction and X-ray diffraction measurements indicate the heteroepitaxial structure of LaB6 (100)/SrB6 (100)/sapphire (0001) with three domains of epitaxial relationship. The prepared films exhibit atomically stepwise surface morphology, similar to that for the substrate, with 0.2-nm-high atomic steps and ~70-nm-wide terraces. LaB6 epitaxial thin films show metallic behavior, with almost constant resistivity (1.0 × 10 Ω cm) in the temperature range 10–300 K, while epitaxial SrB?36 buffer thin films show semiconducting behavior, with a resistivity of 4.8 Ω cm at room tem-perature.