Controllable growth of GeO 2 nanowires with the cubic and hexagonal phases and their photoluminescence

Abstract

Single crystalline GeO 2 nanowires with the cubic and hexagonal structures were synthesized via heating Germanium wafer coated with an Au film at 500–600 °C under the flow of H 2O vapor/N 2. The Germanium wafer was used as both reagent and substrate for the growth of GeO 2 nanowires. The control over the GeO 2 nanowires with the cubic and hexagonal phases, the diameters of 30–75 nm and the lengths of 2.5–200 μm can be achieved by varying the heating temperature and time. The GeO 2 nanowires follow a top-Vapor–Liquid–Solid growth model. Ultraviolet, violet and blue emissions peaked at 351.9, 396.8 and 480.2 nm, respectively, are observed from the GeO 2 nanowires, which indicate that the GeO 2 nanowires may have potential applications in nanoscale photonic and electronic devices. This low temperature Vapor–Liquid–Solid growth process may be employed for the controllable synthesis of other oxide nanowires with different crystalline phases, and provides opportunities for both fundamental research and technological applications.