ZnO Nanowire Formation by Two-Step Deposition Method Using Energy-Controlled Hollow-Type Magnetron RF Plasma

Abstract

ZnO nanowire was produced in RF (radio frequency) discharge plasma. We employed here a two-step deposition technique. In the 1st step, zinc atoms were sputtered from a zinc target to create zinc nuclei on a substrate before the growth of ZnO nanostructure. Here, we used pure argon plasma for physical sputtering. In the 2nd step, we employed an oxygen discharge mixed with argon, where oxygen radicals reacted with zinc nuclei to form ZnO nanostructures. Experimental parameters such as gas flow ratio and target bias voltage were controlled in O 2 /Ar plasma. Properties of the depositions were analysed by SEM and Raman spectroscopy. We found that many folded and bundled nanowires formed in the 2nd step. The diameter of wires was typically 10-100 nm. We also discussed a growth mechanism of ZnO nanowires.

Shadow mask assisted direct growth of ZnO nanowires as a sensing medium for surface acoustic wave devices using a thermal evaporation method

“…Low temperature growth of 1D ZnO nanostructures, such as nanowires [18][19][20], nanorods [19] and nanoneedles [21] has also been reported in the past using RF magnetron sputtering technique. However, the synthesized 1D ZnO nanostructures again had fusion among the roots, either because of the presence of an underlying Zn [18] or ZnO layer [20,21] which assisted the nucleation process, or a bunch of nanowires or nanorods that formed an aggregated microstructure [19]. This, again, reduces the surface area of the nanostructures used for sensing purposes.…”