Junaid, Bushiri M; Mahadevan Pillai, V P; Pradeep, T; Jayasree, R S; Nayar, V U(Elsevier, 1997)
[+]
[-]
Abstract:
FTIR and Raman spectra of FeClMoO4 single crystal and polycrystalline Na2MoO4, Na2MoO4·2H2O and
Na2MoO4·2D2O are recorded and analysed. The band positions for different modes suggest that MoO4 tetrahedron
is more distorted in FeClMoO4. The larger splitting observed for the bending modes and partial retention of
degeneracy of the asymmetric stretching mode indicate that angular distortion is greater than liner distortion in
MoO4 2 ion in FeClMoO4 confirming x-ray data. The non-appearance of the n1 and n2 modes in the IR and partial
retention of the degeneracies of various modes show that MoO4 2 ion retains Td symmetry in Na2MoO4. Wavenumber
values of the n1 mode indicate that the distortion of MoO4 tetrahedra in the four crystals are in the order
FeClMoO4\ Na2MoO4·2H2O\Na2MoO4·2D2O\Na2MoO4. The water bands suggest the presence of two
crystallographically distinct water molecules in Na2MoO4·2H2O. They form strong hydrogen bonds
ZnO micro particles in the range 0.4-0.6 μm were synthesized by microwave irradiation
method. The XRD analysis reveals that the sample is in the wurtzite phase with orientation
along the (101) plane. SAED pattern of the sample reveals the single crystalline nature of
the micro grains. TEM images show the formation of cylindrical shaped ZnO micro
structures with hexagonal faces. The optical phonon modes were slightly shifted in the
Raman spectrum,attributed to the presence of various crystalline defects and laser induced
local heating at the grain boundaries. A broad transmission profile was observed in the
FTIR spectrum from 1550-3400 cm-1 which falls in the atmospheric transparency window
region. PL spectrum centered at 500 nm with a broad band in the region 420-570 nm
comprised of different emission peaks attributed to transition between defect levels.
Various emission levels in the sample were expliained with a band diagram
Description:
Journal of Optoelectronics and Biomedical Materials Vol. 4, Issue 1, January-March 2012, p. 1 - 7
Junaid, Bushiri M; Gopakumar, V; Vaidyan, V K(January 17, 2013)
[+]
[-]
Abstract:
ZnO thin films were coated on amorphous glass substrate at various temperatures in the
range 160-500 0C by spray pyrolysis method. The as deposited films were characterised by
using XRD and SEM. Wurtzite phase of ZnO was formed at a substrate temperature of
400 0C, highly oriented (002) phase was developed with respect to increase of substrate
temperature from 450 to 500 0C. Morphological and growth mode of these films were
analyzed with respect to structural orientation of films from wurtzite to highly (002)
oriented phase. Present study reveals that substrate temperature was one of the important
parameters which determine the crystalline quality, population of defects, grain size,
orientation and morphology of the films
Description:
Journal of Optoelectronics and Biomedical Materials Vol. 5 Issue 1, January - March 2013 p. 1 - 8
Junaid, Bushiri M; Kochuthresia, T C; Athimoolam, S; Ramakrishnan, V; Vaidyan, V K(Scientific Research Publishing, January 10, 2013)
[+]
[-]
Abstract:
Th(BrO3)3·H2O single crystals were grown from its aqueous solution at room temperature. Single crystal XRD, Raman and FTIR techniques were used to investigate the crystal structure. The crystal structure was solved by Patterson method. The as grown crystals are in monoclinic system with space group P21/c. The unit cell parameters are a = 12.8555(18) Å, b = 7.8970(11) Å, c = 9.0716(10) Å, = 90°, = 131.568° and = 90° and unit cell volume is 689.1(2) Å3. Z = 8, R factor is 5.9. The Raman and FTIR studies indicate the lowering of symmetry of bromate anion from C3V to C1. Hydrogen bonds with varying strengths are present in the crystal. The centrosymmetric space group P21/c of the crystal is confirmed by the non-coincidence of majority of Raman and IR bands
Description:
Crystal Structure Theory and Applications, 2013, 2, 70-74
Junaid, Bushiri M; Sajan, P; Vinod, R(Springer, September 13, 2013)
[+]
[-]
Abstract:
Relatively oxygen-free mesoporous cubic ZnS
particles were synthesised via a facile solvo-hydrothermal
route using a water–acetonitrile combination. Boosted UV
emission at 349 nm is observed from the ZnS prepared by
the solvo-hydrothermal route. The increased intensity of this
UV emission is attributed to activation of whispering gallery
modes of almost elliptical microstructures made of porous
nanostructures.