Photoluminescence properties of ZnO nanowire arrays fabricated on silicon substrate

Arrays of single-crystal zinc oxide (ZnO) nanowires have been synthesized on silicon substrates by vapor-liquid-solid growth techniques. The effect of growth conditions including substrate temperature and Ar gas flow rate on growth properties of ZnO nanowire arrays were studied. Structural and optical characterization was performed using scanning electron microscopy (SEM), X-ray diffraction (XRD) and photoluminescence (PL) spectroscopy. The XRD measurements showed that the single crystal nanowires exhibited growth in the (002) direction. SEM images of the ZnO nanowire arrays grown at various Ar gas flow rates indicated that the alignment and structural features of ZnO nanowires were affected by the gas flow rate. The PL of the ZnO nanowire arrays exhibited strong ultraviolet (UV) emission at 380□nm and weak green emission around 510□nm. A blue shift and broadening of the UV emission was observed with an increment of Ar gas flow rate.