Three-Dimensional Structure of Helical and Zigzagged Nanowires Using Electron Tomography
- PDF / 437,787 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 44 Downloads / 150 Views
1144-LL04-02
Three-Dimensional Structure of Helical and Zigzagged Nanowires Using Electron Tomography Han Sung Kim1, Yoon Myung1, Chang Hyun Kim1, Seung Yong Bae2, Jae-Pyoung Ahn3, and Jeunghee Park1* 1
Department of Chemistry, Korea University, Jochiwon 339-700, Korea, Republic of Chemical Research and Development Center, Samsung Cheil Industry Inc., Uiwang 332-2, Korea, Republic of 3 Advanced Analysis Center, Korea Institute of Science and Technology, Seoul 136-791, Korea, Republic of 2
ABSTRACT Electron tomography and high-resolution transmission electron microscopy were used to characterize the unique three-dimensional structures of helical or zigzagged GaN, ZnGa2O4 and Zn2SnO4 nanowires. The helical GaN nanowires adopt a helical structure that consists of six equivalent growth directions with the axial [0001] direction. The ZnGa2O4 nanosprings have four equivalent growth directions with the [001] axial direction. The zigzagged Zn2SnO4 nanowires consisted of linked rhombohedrons structure having the side edges matched to the direction, and the [111] axial direction. INTRODUCTION One-dimensional (1D) nanostructures have attracted considerable attention due to their potential use as building blocks for assembling active and integrated nanosystems.(1) Recently, interest in helical (or spring-like) and zigzagged nanostructures has been steadily increasing, owing to their attractive morphology and properties. It was demonstrated that helical carbon nanotubes (CNTs) and nanowires (e.g., ZnO, InGaAs/GaAs, Cr) can be used as extremely sensitive mechanical resonators to detect mass and pressure changes.(2a,2b,5b,17,18) All of the zigzagged or helical structures in these previous studies were analyzed by examining their twodimensional (2D) projections using transmission electron microscopy (TEM), which provides a first insight into their size and morphology. There are, however, potentially some cases where important three-dimensional (3D) structural information is missed or erroneous information may be obtained when using simply this technique. Electron tomography, which is a method to reconstruct 3D morphologies from a series of 2D images or projections, has been successfully applied to analyze the morphology of nanoparticles as well as their location in a mesoporous matrix (or carbon nanotubes or nanocomposites).(21-28) However, the use of electron tomography to study the 3D geometry of helical or zigzagged nanostructures has not been much reported, despite the ever-increasing research effort devoted to this field. Herein, we report the 3D structures of helical or zigzagged GaN, ZnGa2O4 and Zn2SnO4 nanowires (NWs), obtained by electron tomography and high-resolution TEM. The present work demonstrates their 3D reconstruction images, acquired from a series of 2D projections obtained by high-angle annular dark field (HAADF) scanning TEM (STEM). The results of this study should open up a new field allowing for the investigation of nanostructures with high spatial resolution that could have an impact on our understanding
Data Loading...
