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Alavi S.J.,Ferdowsi University of Mashhad | Khalili N.,Payame Noor University | Kazemi Oskuee R.,Mashhad University of Medical Sciences | Verma K.D.,Material Science Research Laboratory | Darroudi M.,Mashhad University of Medical Sciences
Ceramics International | Year: 2015

Abstract Monodispersed zinc oxide nanoparticles (ZnO-NPs) were synthesized by a simple sol-gel method. In this process, polyethyleneimine (PEI) was used as a polymeric matrix and mild reaction conditions. The PEI acted as a stabilizing or capping agent and polymeric template for preparing ZnO-NPs. The ZnO-NPs were successfully grown at different calcination temperatures, and their crystallite structures were characterized using various methods, including TEM, PXRD, FTIR, and TGA/DTA techniques. The PXRD analysis revealed wurtzite hexagonal ZnO with preferential orientation at (101) reflection plane. Spherical ZnO-NPs were synthesized and its TEM image showed the formation of nanopowders in size of about 25 nm, while dose dependent toxicity with non-toxic effect of concentration below 6.25 μg/mL was observed in the studies of in vitro cytotoxicity on neuro2A cells. © 2015 Elsevier Ltd and Techna Group S.r.l. Source

Shaaban E.R.,Assiut University | Emam-Ismail M.,Ain Shams University | Abbady G.,Assiut University | Prakash D.,Jammu University | And 3 more authors.
Solid State Sciences | Year: 2016

Different compositions of amorphous Ge15Se85-xCux thin films were deposited onto glass substrates by the thermal evaporation technique. Their amorphous structural characteristics were studied by X-ray diffraction (XRD). The optical constants (n, k) of amorphous Ge15Se85-xCux thin films were obtained by fitting the ellipsometric parameters (φ and δ) data for the first time using three layers model system in the wavelength range 300-1100 nm. It was found that the refractive index, n, increases with the increase of Cu content. The possible optical transition in these films is found to be indirect transitions. The optical energy gap decreases linearly from 1.83 to 1.44 eV with increasing the Cu. The experimental transmittances spectrum can be simulated using the thickness and optical constants modeled by spectroscopic ellipsometry model. © 2015 Elsevier Masson SAS. Source

Prakash D.,University | Varshney M.,Material Science Research Laboratory | Verma K.D.,Material Science Research Laboratory | Kumar R.,National Institute of Technology Hamirpur
Science of Advanced Materials | Year: 2012

We report the oriented growth of single phase CeO2 thin films using pulsed laser deposition technique and their structural and optical properties. X-ray diffraction (XRD) measurements confirm the (111) oriented growth of CeO2 thin films on amorphous quartz substrates. The atomic force microscopy (AFM) measurements supported the XRD measurements and depict the formation of larger sized crystallites in annealed films. UV-visible absorption spectra show significant red-shift in the absorption edge and hence, decrease in the band gap energy has been observed in annealed CeO2 film. Raman mode intensity of F2g mode was observed to increase after heat treatment. The photoluminescence (PL) spectra show visible emission from both the samples of as-deposited and annealed CeO2 films. Copyright © 2012 by American Scientific Publishers. Source

Sharma A.,Krishna Institute of Engineering and Technology | Varshney M.,Material Science Research Laboratory | Verma K.D.,Material Science Research Laboratory | Kumar Y.,Pohang Accelerator Laboratory | Kumar R.,National Institute of Technology Hamirpur
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2013

This paper gives detailed investigations on the deposition of SnO thin films, on glass substrates, using RF sputtering technique. To check the stability of SnO phase, under high energy ion irradiation, swift heavy ion (SHI) beam irradiation experiments are performed using 150 MeV Au beams. The effect of irradiation, with three irradiation fluences i.e. 1 × 1011, 1 × 1012, and 5 × 1012 ions/cm2, is investigated by X-ray diffraction (XRD), Raman spectroscopy, and Atomic force microscopy (AFM). The possible mechanism of the structural changes (tetragonal SnO (space group P4/nmm) to orthorhombic SnO (space group Cmc21)) and surface microstructure evolutions is briefly discussed in the light of ion's energy and energy loss processes. © 2013 Elsevier B.V. All rights reserved. Source

Varshney M.,Material Science Research Laboratory | Sharma A.,Krishna Institute of Engineering and Technology | Verma K.D.,Material Science Research Laboratory | Kumar R.,National Institute of Technology Hamirpur
Physica Scripta | Year: 2012

In this work, we report detailed investigations on the structural and magnetic properties of pure and Co-doped CeO 2 nanoparticles. All the samples, with different cobalt concentrations, were prepared by the co-precipitation method. To investigate the structural properties and phases present in the samples, systematic, x-ray diffraction measurements were performed in the θ-2θ mode. Phonon modes, from the pure and Co-doped samples, were studied by Raman scattering measurements. Surface morphology of individual nanoparticles was studied by field emission scanning electron microscopy. Interestingly, room temperature ferromagnetism is observed in, both, un-doped and Co-doped samples. The mechanisms of variation in the Raman active mode (F 2g) and magnetization, by increasing the cobalt concentration, are briefly discussed. © 2012 The Royal Swedish Academy of Sciences. Source

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