Effect of applied voltage on the structural properties of SnO2 nanostuctures grown on indium-tin-oxide coated glass substrates.

SnO2 nanostuctures were formed on indium-tin-oxide (ITO)-coated glass substrates by using an electrochemical deposition (ECD) method. X-ray photoelectron spectroscopy (XPS) spectra showed the existence of elemental Sn and O in the samples, indicative of the formation of SnO2 materials. An XPS spectrum showing the O 1s peak at a binding energy of 531.5 eV indicated that the oxygen atoms were bonded to the SnO2. Field-emission scanning electron microscopy (FE-SEM) images showed that the samples formed by using the ECD method had SnO2 nanostructures with a size between 280 and 350 nm. FE-SEM images showed that the size of the SnO2 nanostructures formed at 65 degrees C for 30 min increased with decreasing applied voltage. X-ray diffraction (XRD) patterns showed that the SnO2 nanostrucures had tetragonal structures with cell parameters of a = 4.738 A and c = 3.187 A. XRD results showed that the peak intensity of the (110) plane increased with decreasing applied voltage, indicative of a preferencial orientation of the (110) plane.

Direct fabrication of zero- and one-dimensional metal nanocrystals by thermally assisted electromigration.

Zero- and one-dimensional metal nanocrystals were successfully fabricated with accurate control in size, shape, and position on semiconductor surfaces by using a novel in situ fabrication method of the nanocrystal with a biasing tungsten tip in transmission electron microscopy. The dominant mechanism of nanocrystal formation was identified mainly as local Joule heating-assisted electromigration through the direct observation of formation and growth processes of the nanocrystal. This method was applied to extracting metal atoms with an exceedingly faster growth rate ( approximately 10(5) atoms/s) from a metal-oxide thin film to form a metal nanocrystal with any desired size and position. By real-time observation of the microstructure and concurrent electrical measurements, it was found that the nanostructure formation can be completely controlled into various shapes such as zero-dimensional nanodots and one-dimensional nanowires/nanorods.

The creation of sub-10 nm In(PO3)3 nanocrystals in an insulating matrix, and underlying formation mechanisms.

Sub-10 nm In(PO(3))(3) nanocrystals (NCs) were created in an insulating matrix by rapid thermal annealing to form nanocomposite structures. On annealing at a temperature of 400 degrees C, P(2)O(5) NCs were formed by substituting P for Zn atoms in ZnO films via the kickout diffusion mechanism based on the fixed oxygen sublattice. On annealing at a higher temperature of 600 degrees C, however, In(PO(3))(3) NCs were nucleated by diffusion of In atoms from the substrate into the sites of P(2)O(5) NCs that coalesced by moving atoms to neighboring grains in the strain relaxed region. The formation mechanisms of sub-10 nm In(PO(3))(3) NCs in an insulating matrix due to rapid thermal annealing are described on the basis of the experimental results.

Structural and electronic properties of ZnO nanoparticles grown on p-Si and Al2O3 substrates by using spin coating and thermal treatment.

ZnO nanoparticles were formed on p-Si and Al2O3 substrates by using spin coating and thermal treatment method. Scanning electron microscopy images and X-ray energy dispersive spectrometry profiles showed that ZnO nanoparticles were formed on p-Si and Al2O3 substrates. X-ray diffraction patterns showed that ZnO nanoparticles formed on the p-Si substrates had polycrystalline hexagonal wurtzite structures and that those formed on the Al2O3 substrates had a c-axis preferential orientation. X-ray photoelectron spectroscopy profiles showed that the O 1s and the Zn 2p peaks corresponding to the ZnO nanoparticles were observed.