Effect of surface treatment of substrates on epitaxial α-Fe 2O 3 films by coating-pyrolysis process

Abstract

Using a coating-pyrolysis process, an α-Fe 2O 3 film, which consists of densely packed epitaxial α-Fe 2O 3 particles with a rectangular shape, was obtained when an iron 2-ethylhexanoate solution was spin-coated onto an α-Al 2O 3 (012) substrate rinsed with methanol, and subsequently annealed in air. When the α-Al 2O 3 substrate was rinsed with other conventional solvents, such as toluene, etc., round-shaped particles were formed on the substrate. Since densely packed rectangular crystals of α-Fe 2O 3 were formed only on the substrate rinsed with methanol, methanol molecules adsorbed on the α-Al 2O 3 substrate are considered to promote α-Fe 2O 3 to form a densely packed layer of rectangular crystals. The ordered adsorption of iron 2-ethylhexanoate molecules through methanol molecules is discussed.