Growth and structure analysis of tungsten oxide nanorods using environmental transmission electron microscopy
The WO3 nanorods were fabricated in environmental transmission electron microscopy (ETEM) by simply heating it in oxygen atmosphere. Altough, WO3 nanorod showed high crystalline, but the stacking fault existed in nanorod. Furthermore, the nanorod was grown on tungsten wire through slit of oxide layer on it.
The Growth Mechanism of a-Fe 2O 3 Ellipsoidal Particles in Solution
Abstract The mechanism of formation of ellipsoidal hematite (α-Fe 2 O 3 ) particles, obtained by homogeneous precipitation from ferric salt solutions under different experimental conditions, is reported. Monocrystalline ellipsoidal particles having an axial ratio of 6, precipitated by aging FeCl 3 solutions in the presence of small amounts of phosphate anions, are formed by an ordered aggregation of smaller ellipsoids. The nature of the forces involved in this process and the role played by phosphate anions are discussed. Ellipsoidal hematite particles (axial ratio 1.65) obtained by aging Fe(NO 3 ) 3 acidic (HNO 3 ) solutions were found to contain a certain amount (≈8%) of goethite (α-FeOOH) in the particle core. A formation mechanism involving the heterogeneous nucleation of hematite on initially precipitated goethite cores is suggested.
LEED from statistical step models
Abstract Several LEED studies have recently been reported on surfaces which were forced to exhibit steps of fairly well defined average separations. The diffraction patterns in each case were qualitatively similar, showing many beams split into multiplets with separations which depended on the incident electron energy. These patterns were interpreted in terms of kinematic scattering from a stepped, two-dimensional array of point scatterers, assuming perfectly ordered steps. Such studies expose LEED as a possible tool for the analysis of surface topography if used in conjunction with an analytical approach which includes arbitrary, statistical step distributions. Such an approach is outlined in the present paper and calculations are performed for simple distributions of step spacings to illustrate the procedure and convey physical insight. The most striking result concerns the degree of scatter in the step lengths that can be tolerated and still produce “sharp” splittings.