Facile fabrication of morphology-tunable SnOx nanostructures by catalyst-free growth

• We investigated the morphological evolution of catalyst-free SnOx nanostructures.
• The different growths of SnOx nanostructures occurs at narrow temperature zones.
• The PL spectra of individual SnOx nanostructures depend on synthesis conditions.

Nanorods (NRs) with square-cross-sections, sword-like NRs, and nanowires (NWs) of SnOx were synthesized by catalyst-free thermal evaporation of Sn powder in the presence of O2 gas. The effects of synthesis temperature on the morphology and photoluminescence are presented. Although it is possible that different growth mechanisms occurs simultaneously in this narrow temperature zone, predominant morphologies clearly appeared as 1-dimensional (1D) NRs, sword-like NRs, and NWs at 900 °C, 925 °C, and 950 °C, respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicate the morphological evolution of various SnOx nanostructures depending on synthesis temperature conditions. The structural properties of these SnOx have been examined by TEM, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The photoluminescence (PL) spectrum of the nanostructures showed two emission bands centered at approximately 440 nm (blue) and 620 nm (orange) originating from structural defects and surface oxygen vacancies in the case of the blue emission and grain/point defects in the case of the orange emission.

SEM images of the evolutionary SnOx nanostructures affected by process temperatures from 900 °C to 950 °C.Figure optionsDownload as PowerPoint slide