Synthesis and photoelectric properties of ZnO nanostructure with different morphologies via hydrothermal method

Abstract

Numerous zinc oxide (ZnO) nanomaterials, with unique physical and chemical properties, have recently been synthesised by various methods. In this study, a hydrothermal method was developed to synthesise ZnO nanomaterials with different morphologies on indium doped tin oxide (ITO), and the growth mechanism was discussed. The structure and morphologies of the synthesised samples were characterised by X-ray diffraction and SEM. The photoluminescence (PL) and field emission characteristics of ZnO nanomaterials with different morphologies were measured. X-ray diffraction and SEM images indicate that ZnO with morphologies of nanocones, nanorods and nanotubes is grown along c axis to the ITO substrates. The room temperature PL spectra reveal a strong and sharp ultraviolet emission band at 386 nm and a weak blue emission band at 470 nm. The field emission measurements show that the turn-on field of ZnO nanocones, nanorods and nanotubes at emission current density of 10 μA cm−2 is approximately 2·62, 4·31 and 3·92 V μm−1. Moreover, the emission image of ZnO nanocones is more homogeneous than that of ZnO nanorods and nanotubes at the electric field of 4·5 V μm−1. The experimental results indicate that ZnO nanomaterials with different morphologies have good photoelectric properties. As cold cathode materials, ZnO has a great number of potential applications for the field emission display in the future.