Photoluminescence of zinc oxide crystals synthesized on zinc wire by electric current heating method

When a Zn wire was heated by electric current, ZnO whiskers grew on the wire surface. The average diameters of the whiskers grown under O2, 20% O2 and Ar atmospheres were 0.12, 0.17 and 0.4 μm, respectively. The well-known visible emission was observed from the whiskers grown under O2 and 20% O2 atmospheres. The whiskers grown under Ar atmosphere showed strong ultraviolet (UV) emission. X-ray diffraction measurements revealed that the crystalline quality of the whiskers increased with decreasing O2 concentration in the growth atmosphere. It was found that residual O2 of less than 10 ppm in Ar atmosphere is used for the synthesis of the whiskers with UV emission. Monitoring O2 concentration during the electric current heating of Zn wire in Ar atmosphere was effective in estimating the yields of the whiskers.