In situ TEM investigation of indium oxide/titanium oxide nanowire heterostructures growth through solid state reactions.

Heterostructured TiO 2 /In 2 O 3 nanowires have been extensively applied in various photonic devices; their performance is highly related to the microstructures, which has not been, however, clearly understood; thus, it is important to investigate the microstructural evolution of the material during processing. In this work, the crystallinity and microstructure of TiO 2 /In 2 O 3 nanowires were successfully controlled with the variation of annealing temperatures via solid-state reactions. The dynamic phase transformation process was demonstrated by in situ transmission electron microscope (TEM). Moreover, the elemental information at different states was identified by energy dispersive spectroscopy (EDS). It is found that different annealing temperatures would contribute to different solid-state reactions and nanowire heterostructures. Additionally, photoresponse studies show characteristics enhancement for such nanoheterostructures. This study provides the knowledge of the fundamental science in kinetics of heterostructured nanostructures, which benefits the improvement of the performance for future photonic applications. [Display omitted] • The solid-state reaction of In 2 O 3 /TiO 2 heterostructured nanowires was investigated by in situ TEM. • The microstructure and crystallinity of TiO 2 were successfully controlled with varying temperatures. • The nanowire would be broken with the reaction length achieving 4.975 times the radius. • A U-shape phase boundary was formed during the diffusion of Ti, resulting from the different diffusion rates of facets. • This study provides the fundamentals in nano-heterostructures, advancing the performance for future photonic applications. [ABSTRACT FROM AUTHOR]