대면적으로 패턴된 산화아연 나노막대/튜브 제조 및 특성 연구

Abstract

One-dimensional nanostructured ZnO materials are of great interest because they display enhanced light absorption/extraction; improved charge transport and large surface to volume ratio making them excellent candidate materials for electronic, optoelectronic, electrochemical, and electromechanical devices. Vertically-alignment of the ZnO nanorods further expands applications because the interface with the substrate can be more uniform with higher element density. This has enabled quasi-3D structured devices to be developed such as vertical FETs, LEDs, laser diodes, biochemical sensors and photovoltaic cells. Even more recently the challenge has become to synthesize uniformly ordered vertically-aligned nanorod arrays with a high symmetry because coupling between nanorods enables collective behavior to emerge. Examples include photonic crystals for optical circuits and designed surface wetting for microfluidics and waterproof electronics. Here we describe a simple, versatile technique to produce large-scale arrays of highly ordered ZnO nanorods. Patterning of three distinct ZnO crystal morphologies is demonstrated through use of different ZnO seed layers. Array formation is accomplished through a simple variation on nanosphere lithography that imprints a thickness variation across a PMMA mask layer. The area of exposed seed layer is controlled through etching time in an oxygen plasma. Subsequent hydrothermal growth from the patterned seed layer produces highquality ZnO crystals in uniform arrays. The high uniformity of the patterned array is shown to induce a high contact angle hydrophobic state even without the need for chemical modification of the ZnO surface. This technique provides a straightforward way to integrate the optical and electrical properties of high-quality ZnO nanorods with the tunable fluidic properties at the surface of well-ordered arrays.