Room temperature synthesis of structure–morphology tuned copper-doped ZnO nanorods and their photo-physics

A facile electrochemical synthesis of crystalline (100) oriented Zinc oxide (ZnO) nanowires on indium tin oxide films is presented. The effect of copper doping in modifying the morphology, structure, photoluminescence and band-gap of ZnO nanorods has also been investigated. Remarkably during the process of Cu doping, although the nanorods retain their crystalline orientation, a lattice expansion, defect generation as well as morphological modifications are observed using X-ray diffraction, Raman spectroscopy and Scanning electron microscopy. Results also confirm a band-gap tuning of the as-synthesized nanorods as well as after Cu doping. A red shift in the band-gap from 3.23, for pristine ZnO nanorods, to 2.37 eV after 10% Cu incorporation is noticed. Significantly, PL results indicate that although the pristine ZnO nanorods are in photoluminescence ON state with highest PL intensity, a PL OFF state (with 98% visible PL quenched) is present after 1% Cu incorporation.