Time evolution of In2O3 rod-like structures in metalorganic chemical vapor deposition process

Abstract

Transparent conduction oxide (TCO) materials exhibit high electrical conductivity, high optical transparency, and high infrared reflectivity. Among TCO materials, indium oxide (In2O3), which is an n-type semiconductor with a wide bandgap, has become the choice for many device applications [1–6]. Since low-dimensional materials have been actively investigated, stimulated by the need for understanding their novel physical and chemical properties different from those in bulk state and for their potential applications to new types of electronic, magnetic, optic, photocatalytic, and energy storage devices [7, 8], the main streams of the present studies have been focused on preparing low-dimensional crystals with special morphologies, such as nanorods, nanowires, dendrite crystals, etc. Accordingly, many means have been developed for the synthesis of the In2O3 one-dimensional (1D) structures [9–19]. In this work, in order to synthesize the In2O3 rod-like structures on silicon (Si) substrates, we have employed the metalorganic chemical vapor deposition (MOCVD) method. We have investigated the variation of the structural properties by conducting the same experiment with different growth time. The products were grown on (001)-oriented Si by MOCVD. A schematic illustration of the MOCVD system was previously reported [20, 21]. The triethylindium (TEI) with Ar carrier gas was supplied into the reactor as indium source and oxygen (O2) was used as oxidizer. The Ar carrier gas flowed through the TEI bubbler maintained at 35 ◦C. The flow rates of O2 and Ar carrier gases, respectively, were 5 standard cubic centimeters per minute (sccm) and 20 sccm, with the growth time ranging from 5 to 60 min. The substrate temperature was set to 350 ◦C. The structural properties were investigated by X-ray powder diffraction (XRD), operating on a Philips X’pert MPD X-ray diffractometer with CuKα radiation. The morphologies of the product were examined by scanning electron microscopy (SEM) (JEOL, JSM-6700F). Fig. 1 shows the cross-sectional SEM images of the products, indicating that the thicknesses of the film-like structures deposited with the growth time of 5, 10, 20, and