Growth of corundum-structured In2O3 thin films on sapphire substrates with Fe2O3 buffer layers

We report the fabrication of rhombohedral corundum-structured indium oxide (α-In2O3) thin films, which can complete a semiconductor quaternary alloy system with α-Al2O3 and α-Ga2O3, on sapphire substrates with α-Fe2O3 buffer layers. X-ray diffraction showed the formation of α-In2O3, and the α-In2O3 film exhibited n-type semiconductor properties with electron concentration of 1.2×1018 cm−3 and electron mobility of 83 cm2/Vs. The α-In2O3 took grain structure with the lateral sizes of 300–600 nm, and in a grain area α-In2O3 grew epitaxially on a sapphire substrate.

► Nearly single-crystalline corundum-structured In2O3 thin films were grown.
► The achievements are indebted to the α-Fe2O3 buffer on sapphire substrate.
► The achievements open the future evolution of (AnGaIn)2O3 alloys, like (AlGaIn)N.
► We discuss the physics of the growth mechanism and of the film properties.