Nucleation mechanism and microstructural assessment of SnO2 nanowires prepared by pulsed laser deposition

Tin dioxide, SnO2, nanowires have been successfully synthesized by a pulsed laser deposition process based on a sintered cassiterite SnO2 target, being deposited on Si (100) substrates at room temperature. Transmission electron microscopy shows that nanowires are structurally perfect and uniform, and diameters range from 10 nm to 30 nm, and lengths of several hundreds nanometers to a few micrometers. X-ray diffraction and energy dispersive X-ray spectroscopy analysis indicate that the nanowires have the same crystal structure and chemical composition found in the tetragonal rutile form of SnO2. Selected area electron diffraction and high-resolution transmission electron microscopy reveal that the nanowires grow along the [110] growth direction. In addition to the fundamental Raman scattering peaks, the other two Raman scattering peaks are also observed. We discussed the possible reasons for the appearance of Raman scattering peaks at 518.7 and 701.8 cm−1. The growth process of the SnO2 nanowires is suggested to follow a vapor-solid mechanism.