C. Balasubramanian

C. Balasubramanian
Institute for Plasma Research · Department of Atomic Energy

Ph.D

About

68
Publications
13,425
Reads
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1,904
Citations
Additional affiliations
January 2009 - present
Institute for Plasma Research
Position
  • Research Officer
September 2003 - September 2008
INFN - Istituto Nazionale di Fisica Nucleare
Position
  • PostDoc Position
Education
July 1997 - January 2003
Savitribai Phule Pune University
Field of study
  • Nanomaterials

Publications

Publications (68)
Article
In the synthesis of alloy nanoparticles via arc evaporation and fast quenching, the composition of the synthesized nanoparticles differs significantly from that of the precursor. The properties of the nanoparticles formed following evaporation of a copper-nickel anode by a helium arc are investigated using a nucleation model coupled to the thermal...
Article
Full-text available
Plasma technology finds applications in many industrial areas. To improve the process efficiency, different plasma forming gases and their mixtures are used. Since CO2 is economical and has high thermal conductivity, it is identified as a potential candidate in plasma material processing. However, the characteristics and merits of CO2 plasma arc in...
Article
Cu2ZnSnS4 (CZTS) as an absorber material has proven its potential for high efficiency solar cells. However, commercial viability for low cost photovoltaic depends on improving its efficiency beyond the existing values which require an understanding of secondary phase formation. In this work CZTS layer of upto one micron thickness is prepared by sul...
Article
Many technological applications demand large amount of nanoparticles with well-defined properties, which is feasible only by using large-scale production methods. In this framework, we have performed structural and local geometric investigations of cobalt oxide nanoparticles synthesized by high temperature arc plasma route in helium and in air atmo...
Article
In the present work, full composition range of NixCd1-xO thin films, from Cadmium oxide to Nickel oxide are prepared with sol-gel chemical synthesis route on corning glass substrates. The Fourier transform infrared spectra provide a direct indication of compositional dependence for different vibrational modes with increasing Ni doping. The microsco...
Article
Full-text available
Among the various methods employed in the synthesis of nanostructures, those involving high operating temperature and sharp thermal gradients often lead to the establishment of new exotic properties. Herein, we report on the formation of Cu-Ni metallic alloy nanoparticles with greatly enhanced stiffness achieved through direct-current transferred a...
Article
In the present work, undoped cadmium oxide (CdO)-and 1% Tin 6 (Sn)-doped CdO thin films were prepared by the sol−gel route. These samples 7 have been analyzed by temperature (T)-dependent (80−500 K) Raman 8 spectroscopy and studied for their lattice dynamics and vibrational density of 9 states. Results indicate that the room T pure CdO thin film ma...
Article
CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gas is being considered as one of the potential plasma forming gases in plasma arc material processes due to its thermophysical properties, cost, and easy availability. The understanding of the thermal behavior of CO <sub xmlns:mml="http://www....
Article
Full-text available
Both zinc oxide (ZnO) and reduced graphene oxide (rGO) are known for its attractive optical properties in their nano form. Here, ZnO-rGO nanocomposites and rGO were prepared via simple and reproducible hydrothermal as well as modified Hummer’s method. Microstructural identification of phase formation and dispersion of ZnO on rGO was confirmed by X-...
Chapter
Plasma here refers to the fourth state of matter which has wide-ranging applications—right from industrial to biomedical. A word of caution: The term “plasma” should not be mixed up with the blood “plasma”—which is entirely different from the fourth state of matter—the subject area of this chapter. The interaction of this plasma—fourth state of mat...
Article
DC transferred arc plasma method was employed for the synthesis of core (Fe) - shell (Fe oxide) nanopowders under N2 and He atmosphere. The phase and elemental composition were studied by X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS) techniques. The structural and magnetic properties were investigated by high-resolution tra...
Article
The local structure of Tellurium nanoparticles synthesized by arc plasma were studied by X-ray absorption spectroscopy. Nanoparticles were characterized by using different techniques to reveal particles size, morphology and composition. Te K-edge EXAFS spectra reveal a structure similar to trigonal Te, where both the inter-chain and intra-chain bon...
Article
In this study, a simple, cost-effective thermolysis route to produce single phase, stoichiometric, hollow Cu2−xS microtubes of varied composition by using Cu(tu)Cl·0.5H2O as a self-sacrificed template is devised. Here, the concentration of the reducing agent (i.e., Na2SO3) is precisely controlled to obtain these Cu2−xS microtubes, which are confirm...
Article
One-dimensional (1-D) multiwalled Silicon Carbide (SiC) nanotubes (SiC-NT) and nanowires (SiC-NW) were synthesized by arc plasma method using a mixture of silicon and carbon powders under an optimized arc current and for two different oxygen partial pressures. These, as-synthesized nanostructures were characterized by XRD, EDX and HRTEM. The result...
Article
Full-text available
Thermal plasma method has been used to process mild steel scrap for nanopowder synthesis by changing the operating current. The phase analysis of the product nanopowders was studied by X-ray diffraction and the chemical composition was studied by energy dispersive spectroscopy. The morphology, particle size and particle size distribution of the sam...
Article
The synthesis of cobalt-based magnetic nanostructures using DC arc discharge technique with varying arc current is reported here. The structural, morphological, compositional and magnetic properties of these nanostructures were studied as a function of applied arc current. Various techniques like X-ray diffraction, transmission electron microscopy,...
Article
Magnetic properties and phase compositions of iron-oxide nanoparticles synthesised by a high temperature arc plasma route have been investigated by Mössbauer spectroscopy and high harmonic magnetic AC susceptibility measurements, and correlated with morphological and structural properties for different synthesis conditions. The Mössbauer spectra pr...
Article
We have used high heat flux plasma synthesis process to grow Co those for the morphology, stoichiometry and the local structure as a function of plasma current. We find that the nanoparticles produced by the thermal plasma method have different shapes and size distribution with the plasma current being a key parameter in controlling the formation o...
Book
Full-text available
Papers presented at the 2nd Bilateral Indo-Italian Workshop NEEM 2015 Rome, Italy October 12-14, 2015 Organized with the support of the Directorate General for the Country Promotion Ministry of Foreign Affairs and International Cooperation by Consorzio Hypatia Department of Science & Technology of India IMEM-CNR Institute for Plasma Research (Ghand...
Chapter
Nanotechnology has made inroads into many areas of applications ranging from medical to metallurgy and optoelectronics to textiles. Prominent among the nanotechnology applications in textile are imparting self-cleaning and anti-bacterial properties to the fabric by using nonmaterial. These two applications have not only been found feasible but also...
Article
Full-text available
Titanium dioxide (TiO2) nanoparticles were prepared by the thermal plasma synthesis; which give a highly crystalline product. Their morphological studies are carried out by using techniques like SEM, EDAX, TEM and SEAD. Crystal size was calculated by XRD using Scherrer equation; which is observed at two current amperes; at 80 A size ranges between...
Article
Iron-oxide nanoparticles have been synthesized by high temperature arc plasma route with different plasma currents and characterized for their structure, morphology and local atomic order. Fe K-edge x-ray absorption spectra reveal distinct local structure of the samples grown with different plasma currents. We have shown that the local disorder is...
Article
Optical absorption spectroscopy of CdI2 –BiI3 layered crystals has been performed in the temperature range of 77–300 K. The main absorption, observed in these crystals at 2.59 eV is related to quantum confined exciton absorption of bimolecular BiI 3 cluster. Low energy absorption peaks at 2.38 eV, 2.06 eV and 1.94 eV can be tentatively assigned to...
Article
Full-text available
a b s t r a c t We report the synthesis of Co-doped CdS nanoclusters (Cd 1−x Co x S) for different doping concentra-tions (x = 0.10, 0.20 and 0.30) and characterization of their structural, optical, and magnetic properties. The structural properties studied by X-ray diffraction revealed hexagonal-greenockite structure and a decrease of the lattice...
Article
Carbon nanotubes (CNT) were synthesized using a DC thermal plasma method. Nanotubes from the cathode were analyzed by electron microscopy and were then studied for their field emission properties. The CNTs were deposited on a tungsten wire, which acted as the cathode. The main aim was to push the distance between the electrodes outside those previo...
Article
Full-text available
The aim of this research is focused on the biological effects of multi wall carbon nanotubes (MWCNTs) on three different human cell types, laboratory animals in vivo, and immunological effects. Large numbers of researchers are directly involved in the handling of nanostructured materials such as MWCNTs and nanoparticles. It is important to assess t...
Article
Little information is available upon the effects of carbon nanotubes (CNT) on the airway barrier. Here we study the barrier function of Calu-3 human airway epithelial cells, grown on permeable filters, after the exposure to commercial single-walled or multi-walled CNT, produced through chemical vapour deposition. To assess changes in the paracellul...
Article
We carried out a systematic study of the electrical properties of carbon nanotube-based polymeric composite materials. Our purpose was the production and characterization of a light, thin and mechanically strong new composite material able to cover electric circuits against external electromagnetic interference. As polymeric matrix we used a commer...
Article
Full-text available
For theoretical simulation on AlN nanotubes (NTs) of different chiralities (armchair-and zigzag-type) and uniform diameters, we have considered their single-walled (SW) 1D periodic models. For this aim, we have performed ab initio DFT calculations on AlN SW NTs using formalism of the localized Gaussian-type atomic functions as implemented in CRYSTA...
Article
Full-text available
We analyse the influence of uncharged N vacancies (neutral F centres), created either under conditions of AlN nanotube growth or by its soft irradiation, on the atomic and electronic structure. Periodic one-dimensional (1D) density functional theory (DFT) calculations on models of defective single-walled nanotubes (SW NTs) allow us to analyse how N...
Article
Full-text available
Carbon nanotubes were synthesized by thermal arc plasma process after optimization of the synthesis parameters. These samples were then analysed by scanning and transmission electron microscopes (SEM and TEM), in order to establish the morphology of the nanostructures. Atomic force microscopy (AFM) and electron diffraction studies were also carried...
Article
Full-text available
Carbon nanotubes (CNTs) were synthesized by a DC thermal plasma method. After optimizing the synthesis parameters such as the pressure, current etc, the synthesized products, and the anodic deposit in particular, were characterized by scanning electron and transmission electron microscopy. The morphology of the product was ascertained to be multiwa...
Article
Different AlN nanosystems (NP) were investigated by using synchrotron radiation spectroscopy. Experiments were performed at the Synchrotron Radiation Facility of the Laboratori Nazionali di Frascati using X-ray absorption near-edge spectroscopy (XANES). Preliminary XANES theoretical analysis at the Al K edge is presented.
Article
Full-text available
The paper reports comparative studies on synthesized aluminium nitride nanotubes, nanoparticles and commercially available micron-sized AlN powder using different spectroscopic techniques: cathodoluminescence measurements (CL), X-ray absorption near edge spectroscopy (XANES) and Fourier-transform infrared spectroscopy (FTIR). Crucial distinctions i...
Article
Full-text available
The results of experiments carried out at the ILL neutron facilities in Grenoble on nanotubes of aluminum nitride synthesized through a DC arc plasma process are presented. We discuss the phonon generalized density of states G(v) of the nanotubes in comparison with bulk AlN. G(v) for the bulk features two main bands at low (about 30 meV) and high (...
Article
Full-text available
We analyze the scattering of 480 MeV positrons in bent crystal lattices carried out at the Beam Test Facility of the INFN – Laboratori Nazionali di Frascati. We observe experimentally that some particles follow the bending of the crystal lattice, presumably being guided by channeling phenomenon, and are deflected through the angles of about 10 mrad...
Article
In the present experiment, the radiation from positrons moving in a periodically deformed crystal was observed for the first time. The spectra of radiation are measured in a wide range of energy. The experimental indication showing the existence of an undulator peak in radiation was obtained at a qualitative level and was confirmed by calculations....
Article
Full-text available
Four models of single-walled AlN nanotubes (NTs), which possess (i) two different chiralities (armchair or zigzag type) and (ii) two different uniform diameters for both types of NTs (1 or 6 nm) have been constructed, in order to analyse the dependence of their properties on both morphology and thickness. Periodic one-dimensional (1D) DFT calculati...
Article
Full-text available
We investigated different AlN nano-systems using spectroscopic methods. Experiments were performed at the Synchrotron Radiation Facility of the Laboratori Nazionali di Frascati using both XANES (x-ray absorption near edge spectroscopy) and FTIR (Fourier transform infrared spectroscopy) techniques in order to investigate materials with both interest...
Article
Transmission electron microscopy (TEM) and electron energy loss near-edge structure (EELNES) revealed the presence of mostly non-oxidised silicon tubular structures among the reaction products synthesized by gas phase condensation technique. Scanning tunneling microscopy (STM) showed a hexagonal atomic arrangement for straight ones. The presence of...
Article
Full-text available
We observe positron bending by a crystal lattice, presumably being guided by a channeling phenomenon, deflecting the beam by about 10 milliradian over a length of I mm of silicon. This technique may lead to the use of the channeling effect for steering particle beams at energies below I GeV, for the purpose of producing beams of low emittance with...
Article
gamma-Fe2O3 particles were prepared, for the first time, using a direct current thermal arc-plasma route. The powder was characterized using X-ray diffraction, Mossbauer spectroscopy, X-ray photoelectron spectroscopy, chemical analysis, vibrating sample magnetometry C and transmission electron microscopy. The high purity, stoichiometry and spherica...
Article
Fluorescent nanoparticles were isolated from both pristine and nitric acid-oxidized commercially available carbon nanotubes that had been produced by an electric arc method. The pristine and oxidized carbon nanotube-derived fluorescent nanoparticles exhibited a molecular-weight-dependent photoluminescence in the violet-blue and blue to yellowish-gr...
Chapter
Full-text available
A series of Silicon crystal undulator samples were produced based on the approach presented in PRL 90 (2003) 034801, with the periods of undulation from 0.1 mm to 1 mm, and the number of periods on the order of 10. The samples were characterized by X-rays, revealing the sine-like shape of the crystal lattice in the bulk. Next step in the characteri...
Conference Paper
Carbon nanotubes are being widely studied for various applications ranging from medical to electronics and also optical devices. They are also being studied for the suitability and applications in aerospace and aeronautical field. A useful application in aerospace that we are studying is the improvement of electrical properties of composites made f...
Conference Paper
We investigated different AlN nano-systems with spectroscopical methods. Experiments were performed at the Synchrotron Radiation Facility of the Laboratori Nazionali di Frascati using both XANES (X-ray Absorption Near Edge Spectroscopy) and FTIR (Fourier Transform Infrared Spectroscopy) techniques in order to investigate materials with both interes...
Article
Films of nanocrystalline γ-Fe2O3 were deposited on silicon substrates by using the technique of electrophoretic deposition. The precursor powder was nanocrystalline γ-Fe2O3, which was synthesized, using DC arc plasma in the oxygen ambient by vapour–vapour interaction in gas phase condensation; at a stabilized arc current of 40A. This powder was cha...
Article
Full-text available
Transmission electron microscopy (TEM), electron energy loss near edge structures (EELNES) and scanning tunneling microscopy (STM) were used to distinguish silicon nanotubes (SiNT) among the reaction products of a gas phase condensation synthesis. TEM images exhibit the tubular nature with a well-defined wall. The EELNES spectra performed on each s...
Article
Accelerator-based sources of hard-photon radiation are a rapidly developing field. Coherent radiation of a particle beam in an undulator is a popular choice. The crystalline undulators with periodically deformed crystallographic planes offer electromagnetic fields of the order of 1000 T and could provide a period L in the sub-millimeter range. In t...
Article
Electrical and mechanical properties of composite materials based on Carbon Nanotubes are considered for aerospace applications. Nanostructured materials gained great importance in the past decade, owing to their wide ranging potential applications in many areas, e.g. mechanical, structural, sensor, biomedical, electronics. Of particular interest a...
Article
Full-text available
A series of Silicon crystal undulator samples were produced based on the approach presented in PRL 90 (2003) 034801, with the periods of undulation from 0.1 mm to 1 mm, and the number of periods on the order of 10. The samples were characterized by X-rays, revealing the sine-like shape of the crystal lattice in the bulk. Next step in the characteri...
Article
Full-text available
Radiation emitted by positrons moving in a periodically deformed crystal has been experimentally observed for the first time. Radiation spectra have been measured in a wide energy range. Experimental evidence has been obtained for an undulator peak in a radiation spectrum, which is qualitatively consistent with calculations. Crystalline undulators...
Article
Full-text available
The DC thermal arc-plasma route is used successfully for the first time for the preparation of magnetite (Fe3O4) powders. The powder is characterized by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Mössbauer spectroscopy and transmission electron microscopy (TEM) techniques. The size of particles increases with increasing arc-plasm...
Conference Paper
Nanostructured materials gained great importance in the past decade, owing to their wide range of potential applications in many areas, e.g. mechanical, structural, sensor devices, biomedical, electronics. A large interest is involved with carbon nanotubes, which can be used as a main constituent of composite materials characterized by exceptional...
Article
Polyimide (Kapton-H), was subjected to atomic oxygen from an electron cyclotron resonance plasma. An optical emission spectrometer was used to characterize the atomic oxygen produced in the reactor chamber. The energy of the ions was measured using a retarding field analyzer, placed near the substrate. The density of atomic oxygen in the plasma was...
Article
Full-text available
Crystalline undulators with periodically deformed crystallographic planes offer coherent electromagnetic fields on the order of 1000T and provide undulator period L in submillimeter range. We present an idea for creation of a crystalline undulator and report its realization. One face of a silicon crystal was given periodic microscratches (grooves)...
Article
Nanostructures of cubic aluminium nitride were synthesized by DC arc-plasma-induced melting of aluminium in a nitrogen–argon ambient. The material flux ejected from the molten aluminium surface was found to react with nitrogen under highly non-equilibrium conditions and subsequently condense on a water-cooled surface to yield a mixture of nanowires...
Article
We report the first observations of AlN nanotubes in twisted and helicoidal arrangements, with clear indications of hexagonal atomic arrangement. The AlN nanotubes, synthesized by gas phase condensation using solid–vapor equilibrium, were dispersed on a highly oriented pyrolitic graphite substrate and analyzed by Scanning Tunneling Microscopy. The...
Article
This letter reports the field emission measurements from the nanotubes of aluminum nitride which were synthesized by gas phase condensation using the solid-vapor equilibria. A dc arc plasma reactor was used for producing the vapors of aluminum in a reactive nitrogen atmosphere. Nanoparticles and nanotubes of aluminum nitride were first characterize...
Article
Nanophase alumina (Al2O3) was synthesized in a d.c. arc plasma reactor under isochronal oxygen flow conditions. Transmission electron microscopy revealed spherical particles (50 nm) and the corresponding electron diffraction showed a δ-Al2O3 phase. Structural morphology by X-ray diffraction (XRD) evidenced the phase changes. These measurements conf...
Article
Full-text available
Carbon nanotubes (CNT) were made by DC thermal plasma method and CVD (Chemical Vapor Deposition). After optimizing the synthesis parameters like the pressure, current etc., the products was characterized by electron microscopies like Scanning Electron and Transmission Electron Microscopies. The morphology of the product was ascertained to be multiw...

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