A Feasible Routine for Large-Scale Nanopatterning via Nanosphere Lithography

Abstract

Due to the unique electronic, optical, catalytic and biological properties, well ordered nanostructures have attracted enormous interest. They have potential applications in photonic crystal devices (Yablonovitch, 1987), large-density magnetic recording devices (Chou et al., 1994), novel electronic devices (Schmidt & Eberl, 2001), synthesis of DNA electrophoresis mediate (Volkmuth & Austin, 1992),nanocontainers (Chen et al., 2008), surface-plasmon resonance biosensors (Brolo et al., 2004), antireflective coatings for solar cells (Yae et al., 2005), and etc. Such broad applications of nanostructures were intimately associated with their unique properties, which are sensitively dependent on their size and/or shape. It is well-established that magnetic (Shi et al., 1996; Zhu et al.,2004), optical (Aizpurua et al., 2003; Larsson et al. 2007), electrocatalytic (Bratlie et al., 2007; Narayanan & El-Sayed, 2004), optoelectronic (Chovin et al., 2004), data storage (Ma, 2008), thermodynamic (Volokitin et al., 1996; Wang et al., 1998) and electrical transport (Andres et al., 1996; Bezryadin et al., 1997) properties of the nanostructures are affected by the shape and the size, as well as the interfeature spacing. In general, there are two approaches to realize ordered nanostructures with desired size, shape and arrangement. One is the “bottom up” approach on pre-patterned substrates (Zhong et al, 2007; Zhong et al., 2008). The other is the “top-down” approach (Ito & Okazaki, 2000). Both of these two approaches are always based on lithographic technology. In the first approach, lithographic techniques were employed to fabricate various patterned substrates, on which ordered nanostructures can then be realized by subsequent growth of desired materials. The main reason for this approach is to suppress defects in the nanostructures. In the second approach, ordered nanostructures can be directly fabricated by lithographic techniques. Several standard lithographic techniques are frequently exploited to fabricate desired surface nanostructures, including holographic lithography, electron-beam lithography (EBL) and ion-beam lithography (IBL) (Arshak et al., 2004;Ebbesen et al., 1998; Ito & Okazaki, 2000). Recently, a new extreme ultraviolet (EUV) lithography was developed, which is a potential candidate for achieving critical dimensions below 100 nm (Service, 2001). In addition, there are some other lithographic techniques applied in the fabrication of nanostructures (Haynes & Van Duyne, 2001). However, fabrication of nanostructures in a regular arrangement over large areas is still a major challenge in modern nanotechnologies. There is substantial interest in developing new technologies to facilitate pattern fabrication.