Three growth modes and mechanisms for highly structure-tunable SnO2nanotube arrays of template-directed atomic layer deposition

Abstract

This article presents a vapor-phase strategy to synthesize highly structure-tunable SnO₂ nanotube arrays of high aspect ratio, which features atomic layer deposition of SnO₂ on anodic aluminium oxide templates using SnCl₄ and H₂O as precursors. This systematic study disclosed that there are three distinctive temperature-dependent growth modes, i.e., layer-by-layer, layer-by-particle, and evolutionary particles contributing to the structural uniqueness of the resultant SnO₂ nanotubes. The layers were identified in an amorphous phase while the particles in a crystalline phase. As a consequence, the synthesized SnO₂ nanotubes are not only phase-controllable but also morphology-transferable with growth temperatures. In a following effort to explore the underlying mechanisms, as another contribution of this study, three growth models were proposed and clarified. Thus, this study offers not just a precise alternative for synthesizing structurally novel nanotubes but scientific insights into fundamentals as well.