Time filter

Source Type

Ramanathapuram, India

Valanarasu S.,Arul Anandar College | Dhanasekaran V.,Alagappa University | Karunakaran M.,Sethupathi Government Arts College | Chandramohan R.,Sree Sevugan Annamalai College | Mahalingam T.,Karunya University
Journal of Nanoscience and Nanotechnology

Cobalt Oxide (Co3O4) thin films have been successfully coated onto glass substrates at various solution pH by sol-gel spin coating technique. The film thickness was estimated using weight gain method and it revealed that the film thickness increased with solution pH values. The prepared film structural, morphological, optical and electrical properties were studied using X-ray diffraction (XRD), scanning electron microscope (SEM), UV-Vis-NIR spectrophotometer and Vander Pau method, respectively. The structure of the films were found to be face centered cubic with preferential orientation along (311) plane. X-ray line profile analysis was used to evaluate the micro structural parameters such as crystallite size, micro strain, dislocation density and stacking fault probability. The crystallite size values are increased with increase of solution pH values and maximum value of crystallite is estimated at 40.8 nm at solution pH 8 ± 0.1. Morphological results showed that the pH of the solution has a marked effect on morphology of the Co3O4 thin films. The optical studies revealed that the band gap can be tailored between 2.16 to 2.31 eV by altering pH. The thin film formed at a solution pH 7 is found to have a low resistivity and high mobility. The electrical resistivity (ρ), carrier concentration (n) and mobility (μ) values are 0.1 × 103 Ω cm, 8.9 cm2 γs-1 and 6.6 × 1014 crrr3, respectively for Co3O4 thin film prepared at solution pH 7 ± 0.1. EDAX studies showed that the cobalt content increased and the oxygen content decreased with increase of pH. Copyright © 2014 American Scientific Publishers All rights reserved. Source

Ravikumar S.,Alagappa University | Raja M.,Sethupathi Government Arts College | Gnanadesigan M.,Alagappa University
Natural Product Research

The antibacterial activities of column chromatography fractions of n-hexane, benzene, chloroform, acetone, ethanol and water extracts from Acanthus ilicifolius were tested against 24 bacterial pathogens. The antibacterial activity was performed using agar diffusion method. Most active fractions were further investigated through UV-Vis, 13C, 1H-NMR, FT-IR for the structural elucidation. The antibacterial activity of the extracts was identified as 6-hydroxy-benzoxazolinone, (Z)-4-coumaric acid 4-O-β-D-glucopyranoside and 3,5-dimethoxy-4-hydroxy methyl benzoate. © 2012 Taylor & Francis Group, LLC. Source

Valanarasu S.,Arul Anandar College | Kathalingam A.,Dongguk University | Rhee J.-K.,Dongguk University | Chandramohan R.,Sree Sevugan Annamalai College | And 2 more authors.
Journal of Nanoscience and Nanotechnology

Fabrication and characterization of memory devices using ZnO nanorod layer grown by chemicalbath method is reported. The fabricated memory device was found exhibit electrical bistability and nonvolatile memory phenomenon. An additional Polymethylmethacrylate (PMMA) polymer layer coated on ITO substrate prior to nanorod deposition has been found improve the LRS/HRS ratio of the device. The current-voltage characteristics of the memory devices are discussed in terms of formation and rupture of conductive filaments. The devices have shown consistent electrical bistable behavior even for 105 resistance-switching cycles. This hybrid ITO/PMMA-ZnO NRs/Al device has potential applications in the field of bistable random access memories. Copyright © 2015 American Scientific Publishers All rights reserved. Source

Valanarasu S.,Arul Anandar College | Dhanasekaran V.,Sejong University | Karunakaran M.,Sethupathi Government Arts College | Vijayan T.A.,Sree Sevugan Annamalai College | And 4 more authors.
Digest Journal of Nanomaterials and Biostructures

Magnesium aluminum oxide (MgAl2O4) thin films were prepared by sol-gel spin coating method. The as-prepared films were calcined at 500oC for 12, 18 and 24 hours. The calcinated films were exhibited with polycrystalline in nature cubic structure. (311), (400) and (440) diffracted lines were preferentially oriented in MgAl2O4 thin films. The crystallite size, lattice constant, microstrain, dislocation density, stacking fault probability and number of crystallites were calculated to study the indeed microstructural analysis of MgAl2O4. Tauc’s plots were used to estimate the optical band gap energy and were observed in the range of 3.11-3.33 eV for 12-24 hours calcined MgAl2O4 thin films, respectively. The optical dispersion parameters were calculated using Spitzer-Fan model. Also, other refractive indices and complex dielectric constants were intensely discussed. The morphological studies were depicted the surface nature of the films. The electrical conductivity and activation energy values were discussed with calcinating time variations. © 2015, Inst Materials Physics. All rights reserved. Source

Valanarasu S.,Arul Anandar College Karumathur | Dhanasekaran V.,Aristotle University of Thessaloniki | Karunakaran M.,Sethupathi Government Arts College | Vijayan T.A.,Sree Sevugan Annamalai College | And 2 more authors.
Journal of Materials Science: Materials in Electronics

In the present study, we have reported on the effect of annealing time variations for spin coated magnesium oxide (MgO) thin films. The various time annealed MgO thin films structural, surface morphological, compositional, electrical and optical absorption properties were studied by X-ray diffraction, scanning electron microscopy, energy dispersive analysis by X-rays, I-V studies and UV-vis spectroscopy, respectively. The cubic structure formation with preferential orientation along the (200) plane was confirmed from structural analysis. In addition, the influence of the annealing on the microstructural properties of MgO was plausibly explained. The optical properties of MgO thin films were estimated using the transmission spectrum in the range of 400-800 nm. The optical band gap energy of MgO thin films was found to be in the range between 3.81 and 3.93 eV. The morphological studies depicted that the spherical and ellipsoid shaped grains were distributed evenly over the entire surface of the film. The sizes of the grains are found to be in the range between 200 and 250 nm. The composition analysis was performed by EDX for various temperatures annealed MgO thin films. © 2014 Springer Science+Business Media New York. Source

Discover hidden collaborations