Self-catalytic Branch Growth of SnO 2 Nanowire Junctions
- PDF / 1,056,791 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 2 Downloads / 166 Views
M5.36.1
Self-catalytic Branch Growth of SnO2 Nanowire Junctions Y. X. Chen, L. J. Campbell, and W. L. Zhou Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148. ABSTRACT Multiple branched SnO2 nanowire junctions have been synthesized by thermal evaporation of SnO powder. Their nanostructures were studied by transmission electron microscopy and field emission scanning electron microcopy. It was observed that Sn nanoparticles generated from decomposition of the SnO powder acted as self-catalysts to control the SnO2 nanojunction growth. Orthorhombic SnO2 was found as a dominate phase in nanojunction growth instead of rutile structure. The branches and stems of nanojunctions were found to be an epitaxial growth by electron diffraction analysis and high resolution electron microscopy observation. The growth directions of the branched SnO2 nanojunctions were along the orthorhombic [110] and [1 1 0]. The growth of SnO2 nanojunction is controlled by a self-catalytic vapor-liquid-solid growth using Sn nanoparticle catalysts. INTRODUCTION Recently, one-dimensional (1D) nanowire junctions have attracted much attention because of their potential applications in nanoelectronics [1,2]. 1D nanojunctions have been successfully synthesized by using various methods including laser ablation [1], template-based method [2], thermal chemical vapor deposition [3], and thermal evaporation [4-6], etc. Thermal evaporation has been demonstrated to be an effective method to synthesize 1D metal oxide semiconductor branched nanojunctions, such as ZnO and In2O3-ZnO heterojunctions [4-6]. Among metal oxide semiconductor materials, SnO2 has been actively studied because of its potential applications in optoelectronic devices and chemical sensors [7-9]. 1D SnO2 and In-doped SnO2 with morphologies of nanowire, nanobelt, nanoribbon, and nanotube have been fabricated by a thermal evaporation approach [10-13]. However, no SnO2 nanojunction growth has been reported from direct thermal evaporation of SnO powder. The growth of SnO2 and its doped nanowires was either directly controlled by a vapor-solid (VS) mechanism or catalyst assisted by a vapor-liquid-solid (VLS) model. Catalysts have been exploited to control 1D nanowire growth, where the diameter and length of 1D nanowires are supposed to be controlled by the catalyst size and growth time. Metallic Sn has been reported to be an effective catalyst to control the growth of ZnO nanowire-nanoribbon junction arrays using a thermal evaporation method [4], probably because of its low melting point, i.e. 231.89oC [14]. Self-catalytic growth of SnO2 nanowires catalyzed by Sn nanoparticles has also been reported [12]. However, the behavior of the Sn nanoparticle catalysts in the thermal evaporation process is not fully understood yet. To explore branched
M5.36.2
nanojunction growth and get insight into catalytic nature of Sn nanoparticles, we synthesized SnO2 nanostructures by direct thermal evaporation of SnO powder at an elevated temperature. Besides the expected SnO2 n
Data Loading...
