Two-Dimensional Organization of Single Crystal ZnO Nanopillars
- PDF / 446,589 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 48 Downloads / 145 Views
0957-K07-15
Two-Dimensional Organization of Single Crystal ZnO Nanopillars Jingbiao Cui1 and Ursula J. Gibson2 1 Department of Physics and Astronomy, University of Arkansas at Little Rock, Little Rock, AR, 72204 2 Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755 ABSTRACT Periodically ordered ZnO nanopillar arrays were fabricated by a combination of soft templates created by electron beam lithography and an electro-chemical process. Growth at 90 °C in an aqueous solution ensured compatibility with the polymethyl methacrylate used as a template material. We demonstrate that individual ZnO nanopillars with diameters around 100 nm can be precisely placed in desired locations to form two-dimensional periodic structures. This approach provides a new method for design and fabrication of ZnO photonic materials. The process is compatible with current microfabrication techniques and may have potential applications in the manufacture of photonic and optoelectronic devices.
INTRODUCTION Recently there has been great interest in the investigation of ZnO nanowire arrays due to their potential applications in electronics, photonics and sensors. Dense randomly aligned ZnO nanowire arrays have been obtained using both catalytically activated vapor phase processes at high temperature and hydrothermal solution routes at low temperature [1-6]. Since many applications such as photonic devices require spatial control of individual nanowires, a number of investigations have been devoted to the patterned growth of ZnO nanowire arrays using both vapor phase [7-11] and solution routes [12]. In high temperature vapor phase growth, controlling the size and location of Au catalyst on the substrate surface has been used for the placement of ZnO nanowires. Yang and colleague realized the growth of ZnO nanowires on a photo-lithographically created Au pads on an Al2O3 substrate in a vapor phase process [7]. Due to the limitation of photolithography, each patch is of micrometer dimensions and contains tens to hundreds of ZnO nanowires. Both phase shift photolithography and electron beam lithography were used to create ordered arrays of Au pads with size down to 50-200 nm [8,9]. Several nanowires were found to grow on each site without uniformity. Recently, self-assembly monolayers (SAM) of sub-micrometer spheres with a hexagonal close-packed structure were also applied to create Au islands for ordered ZnO nanowire growth [10,11]. However, this technique lacks the capability for designing and creating desired defects in the ordered structures. The solution routes to ZnO nanowire growth possess numerous advantages including low temperature and little limitation in substrate selection, low cost, and scale-up possibilities. Hsu et al [13] realized the directed micron-level spatial organization of ZnO nanorods on a silver coated Si substrate through inhibition of ZnO nucleation using a contact-printed self-assembled monolayer. In this study, we demonstrate that individual single crystal ZnO nanowires can be precisely organized using
Data Loading...
