Papers by Author: Xiao Jing Kou

Abstract: The optical properties of two kinds of single-wall silicon nanotubes (sw-SiNTs) [(n, 0) and (n, n)] with small diameters are investigated by using the first-principles method. For these two kinds of nanotubes, the absorptive part  of dielectric functions exhibits a broad band from 4 to 8eV in the region of 4-11eV, which is attributed to the transition of the  band to the * and  bands. Particularly, another small peak (inter- band transition) at 1.2-2.3 eV in the low-energy region is also identified. In addition, the loss function of these nanotubes are calculated and discussed.

Abstract: The microstructure and ferroelectric domains of SrBi2Ta1.6Nb0.4O9 ceramics were investigated by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) equipped with energy dispersive spectroscopy (EDS). The X-ray diffraction patterns show that the lattice constants a and b decrease, and c increases by doping with Nb into SBT sample. Accordingly, it has large strain and lattice distortion in the lattice This suggests that the Nb atoms partially occupy the location of the Ta atoms in the lattice. From TEM observations, the grains show (008) preferred orientations in the sample, which agrees well with the XRD results. The 90° domain walls are identified by the 90° rotation relationship of the electron diffraction pattern about the [001] zone axis. The 180° domain walls and anti-phase boundaries (APBs) in Nb-doped SBT ceramics are also observed, which are irregularly shaped and highly curved. The traditional α-fringes can be found in the Nb-doped SBT ceramics, which are the evidence of large strains in the lattice.