Suppression of vapor-liquid-solid (VLS) mechanism in the growth of α-Sb2O4 nanobelts by a vapor-deposition approach

Abstract

In this work we report on the synthesis of novel α-Sb2O4 nanostructures synthesized by a gold catalyzed vapor deposition method in which metallic Sb is used as a precursor. Belts, rods and zigzag morphologies were obtained and characterized by a group of techniques which also provided data on crystalline structure and compositional aspects. Structural characterizations revealed that although the addition of gold nanoparticles plays an important role in the final growth of the nanostructures, no evidence of this element was found in the as-grown samples. In order to clarify the causes of the suppression of the VLS mechanism in these conditions, we carried out experiments in which the syntheses were interrupted in a controlled manner. Our findings revealed that at the early stages of the growth VLS mechanism is suppressed when high levels of Sb supersaturation are reached. A thick crystalline oxide layer rapidly grows at the liquid-gas interface providing preferential sites for the VS growth to take place. Low temperature photoluminescence measurements revealed a strong emission in the visible portion of electromagnetic spectra which can be associated to the presence of oxygen vacancies in these nanostructures.