Morphology of ZnO nanorods and Au–ZnO heterostructures on different seed layers and their influence on the optical behavior

Abstract

Zinc oxide nanorods were synthesized by low cost and low temperature chemical synthesis path by taking both ZnO and metal as the seed layer on the silicon substrate. The morphological study depicts seed layer as one of the key parameter in the growth process. ZnO NR/Au nanoparticles heterostructures were also fabricated. The enhancement of the visible emissions of the ZnO nanostructures is seen after the incorporation of gold nanoparticles at the surface. The visible (defect) emission corresponds to the yellow emission caused by oxygen interstitials. Luminescence vary considerably with position on the nanorod. The optical band gap obtained for Au–ZnO heterostructure to be 2.63 eV, which is lower than that of ZnO NRs. This changing trend of optical band gap for prepared Au/ZnO sample originated from the variety of defects. Tuning of the band gap energy of such wide band gap semiconductor is highly important for room temperature optical devices.