The study of ZnO nanostructures grown on various Si and SiO2 substrates

Abstract

Zinc oxide (ZnO) nanorods have shown very unique properties for applications such as gas sensors, electronics, biotechnological applications, and light emitting diode (LED). In genral, as-synthesized ZnO nanorods have n-type semiconducting properties. The effects of Si substrate orientation and surface treatment on the morphology and density of ZnO nanorods were investigated. The size and density of ZnO nanorods were influenced by Si substrate orientation and surface preparation. We report the structural and optical properties of ZnO nanorods grown on various silicon substrates by chemical bath deposition (CBD) method in aqueous solution using zinc nitrate hexahydrate (Zn(NO3)2•6H2O) and hexamethylenetetramine (HMT : C6H12N4) under same conditions. Various substrates having different surface morphology are used to evaluate their effect on growing ZnO nanorods, such as flat Si(100) wafer, textured Si wafer, porous silicon, flat SiO2 wafer, textured SiO2 wafer. The length, diameter, geometry, and coverage density of ZnO nanorods are investigated by field-emission scanning electron microscopy. Grazing-angle X-ray diffraction and photoluminescence are also measured for each nanorod grown on various substrates.