Towards a highly-controllable synthesis of copper oxide nanowires in radio-frequency reactive plasma: fast saturation at the targeted size

Abstract

Nanoscale copper oxide is a material in high demand, playing a pivotal role in many nanostructure-based emerging applications. Some unique electrical and mechanical properties of these new generation nanostructures are that they are potentially able to boost the characteristics of sophisticated modern electronic devices. Nevertheless, a nontrivial technique commonly used for the synthesis of CuO/CuO2 nanostructures (particularly in nanowires) as well as very complicated growth and nucleation mechanisms, are their stumbling blocks, significantly hindering the occupation of a relevant application niche. In this paper, we theoretically and experimentally demonstrate that the ultramodern radio-frequency plasma-based fabrication technique ensures avoiding highly unfavourable, uncontrollable growth intrinsic to the commonly used thermal oxidation method. Moreover, it enables switching the process to a rapid, target-saturating mode leading to fast, highly controllable nucleation and growth of thin, long, densely packed, highly crystalline copper oxide nanostructures directly on the copper surface, without involving any additional precursors and catalysts in the process. Multiscale numerical simulations reveal the basic mechanisms behind the target-saturating growth mode and the key control factors enabling highly predictable synthesis of dense oxide nanostructures of pre-determined size and surface density.