Model for Hydrothermal Growth of Rutile Wires and the Associated Development of Defect Structures
journal contributionposted on 03.09.2014, 00:00 by Andreas Wisnet, Sophia B. Betzler, Rachel V. Zucker, James A. Dorman, Peter Wagatha, Sonja Matich, Eiji Okunishi, Lukas Schmidt-Mende, Christina Scheu
Crystal defects play a major role in determining the electrical properties of semiconductors. Hydrothermally grown TiO2 rutile nanowire arrays are frequently used as electrodes in photovoltaic devices. However, they exhibit a characteristic defect structure that may compromise performance. A detailed scanning and transmission electron microscopy study of these defects reveals their internal structure and is suggestive at their origin. We propose an anisotropic layer-by-layer growth model, which combined with steric effects and Coulombic repulsion on high atom-density facets, can explain the observed V-shaped defect cascade in the nanowires.