High-resolution nanosphere lithography (NSL) to fabricate highly-ordered ZnO nanorod arrays

Here we report our successful development of a high-resolution, low-cost, simple and convenient technique based on nanosphere lithography (NSL) to fabricate large-scale periodic gold nanoparticle pattern, which is the most common catalyst material in the synthesis of nanostructure and also a feature material for surface plasmon resonation (SPR) research. In order to improve lithography resolution by PS nanosphere self-assembling monolayer (SAM), we adapted the following steps in our fabrication strategy. The original continuous etching by oxygen plasma was replaced by multiple short treatments to avoid heating effect. In addition, direct oxidation was utilized to remove the nanospheres instead of the supersonic process. Using the obtained Au nanoparticle pattern, ZnO nanorod arrays with an average diameter of 50 nm were easily obtained by 600 nm PS nanospheres SAM, which was even smaller than the minimum size by utilizing 400 nm nanospheres SAM in the previous work. Thus, we succeeded in the fabrication of highly-ordered ZnO nanorod arrays with largely tunable diameter by this higher-resolution nanosphere lithography. We also present X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL) and Raman results of our as-grown samples, indicating great crystallization quality and optical property.