Tailoring the shape of oxide complex nanostructures
Authors: Mendez B., Lopez I., Alonso-Orts M., Sanz A., Nogales E., Hidalgo P., Piqueras J.
Autors Affiliation: Univ Complutense Madrid, Dept Fis Mat, E-28040 Madrid, Spain; CNR, INO, Via Carrara 1, I-50019 Sesto Fiorentino, FI, Italy
Abstract: The synthesis of complex nanostructures that combine materials and dimensionality, promises the ability to identify novel designs and architectures with enhanced properties that could be used in new devices. One of the building blocks in nanomaterials are nanowires, which offer several possibilities to get complex nanostructures. We present two kinds of morphologies based on oxide nanowires obtained by a thermal evaporation method. The common feature of both morphologies is a central oxide nanowire and, depending on the growth parameters, nanowires with either nanocrystallites or nano/microrods attached to the central wire are obtained. We have previously reported the fabrication of several single oxide nanowires and in particular, gallium oxide (beta-Ga2O3) and zinc germanate oxide (Zn2GeO4) nanowires. Here we report the shape evolution of these nanowires by the suitable modification of the growth parameters. The addition of tin oxide (SnO2) to the precursors and variation of the thermal treatments duration result in the formation of the above-mentioned complex nanostructures. Structural and chemical characterizations were performed by electron microscopy techniques and Raman spectroscopy. The results shed light on the understanding of the driving mechanisms that lead to the formation of complex oxide nanostructures.
KeyWords: semiconducting oxide nanowires; gallium and tin oxide; germanates nanowires; electron microscopy; thermal evaporation method; Raman spectroscopy