Vapor-phase growth of single-crystal defect-free nanowires: Interface dynamics, morphology control, and emerging applications

Nanowire-based technologies in electronics, photonics, and sensing demand high-quality nanowires with precise control over structure, morphology, and composition. Vapor-phase growth, such as vapor–liquid–solid and vapor–solid–solid, has enabled the controlled synthesis of elemental, group III–V, group II–VI, and a few oxide nanowires; however, many challenges remain. This review highlights the interface dynamics at the seed by comparing conventional growth with an unconventional set-up that has demonstrated success in controllably synthesizing single-crystal, defect-free oxide nanowires. Dynamic aspects are amplified when the substrate itself thermally evaporates at elevated temperatures to generate vapor species that are subsequently encapsulated on gold seeds, enabling nanowire growth at rates of ∼200 nm/min. This review examines the structural characteristics of gold–oxide interfaces, given their critical role in mediating key growth steps, ranging from oxide mass transport across vapors to solid phases, to nucleation and lateral growth at the nanowire growth front. Examples demonstrating how control over interface dynamics can tune nanowire morphology and functionality are presented. We anticipate that this review will provide an alternative perspective on addressing some fundamental processes in vapor-phase nanowire growth and provide valuable insights for further expansion of nanowire synthesis to new materials systems and applications.