Thermal-induced phase transition and assembly of hexagonal metastable In sub(2)O sub(3) nanocrystals: A new approach to In sub(2)O sub(3) functional materials

This paper reports on the thermal-induced performance of hexagonal metastable In sub(2)O sub(3) nanocrystals involving in phase transition and assembly, with particular emphasis on the assembly for the preparation of functional materials. For In sub(2)O sub(3) nanocrystals, the metastable phase was found to be thermally unstable and transform to cubic phase when temperature was higher than 600 C, accompanied by assembly as well as evolution of optical properties, but the two polymorphs coexisted at the temperature ranging from 600 to 900 C, during which the content of product phase and crystal size gradually increased upon increasing temperature. The assembly of In sub(2)O sub(3) nanocrystals can be developed to fabricate In sub(2)O sub(3) functional materials, such as various ceramic materials, or even desired nano- or micro-structures, by using metastable In sub(2)O sub(3) nanocrystals as precursors or building blocks. The electrical resistivity of In sub(2)O sub(3) conductive film fabricated by a hot-pressing route was as low as 3.72x10 super(-3) [Omega] cm, close to that of In sub(2)O sub(3) single crystal, which is important for In sub(2)O sub(3) that is always used as conductive materials. The findings should be of importance for both the wide applications of In sub(2)O sub(3) in optical and electronic devices and theoretical investigations on crystal structures.