Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5355652 | Applied Surface Science | 2016 | 15 Pages |
Abstract
Molecular beam epitaxy of tungsten trioxide (WO3) on (011¯2)-oriented (r-plane) sapphire substrates and molybdenum trioxide (MoO3) on the WO3 was studied by focusing on their crystallogrhaphic properties. Although polycrystalline monoclinic (γ-phase) WO3 films were grown at 500 °C and they became single-crystalline (0 0 1)-oriented γ-phase at 700 °C, the latter films were oxygen-deficient from stoichiometry and contained dense and deep thermal etchpits. By using a two-step growth method where only the initial 15 nm was grown at 700 °C and the rest part was grown at 500 °C, (0 0 1)-oriented γ-phase single-crystalline WO3 films with stoichiometric composition and smooth surface were obtained. On top of the 15-nm-thick WO3 initiation layer, (1 1 0)-oriented orthorhombic (α-phase) MoO3 films with smooth surface were obtained.
Keywords
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Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Mitsuaki Yano, Kazuto Koike, Masayuki Matsuo, Takayuki Murayama, Yoshiyuki Harada, Katsuhiko Inaba,