@article { ISI:000227170600016, title = {Gradual transitions in morphology of diamond films grown by using N-2 admixtures of CH4+H-2 gas in a hot filament assisted chemical vapour deposition system}, journal = {Diamond and Related Materials}, volume = {14}, number = {2}, year = {2005}, month = {FEB}, pages = {232-242}, publisher = {ELSEVIER SCIENCE SA}, type = {Article}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

A study of the evolution of morphology of diamond films grown as a function of N-2 gas additions to the CH4+H-2 precursor in an HF-CVD system is presented. With the increase of admixture of N2 fraction, in contrast to earlier studies, the morphology was observed first to gradually change from {111}-faceted crystallites texture to that of an intermediate cubo-octahedral crystallite texture and then gradually but finally to transform completely into that of {100}-faceted crystallites. The threshold nitrogen concentration, [N-2](thr), required to bring about the said transition in morphology was much larger than it was reported previously. Moreover, the morphology transition required a larger [N-2](thr) when a large fraction of methane was employed. Further additions of nitrogen, that just exceeded the [N-2](thr), resulted in growth of films containing slightly bigger {100}-multi-layered grains or isolated planar {100}-platelets. For extremely large nitrogen additions, the growth of nanocrystalline or amorphous carbon films was observed. The N-2 additions more than 50 vol.\% did not yield any deposition. Raman scattering and photoluminescence measurements were used respectively for characterizing the quality and nitrogen doping in the films. These results are attributed to the possible catalytic role of atomic nitrogen at the growing surface. (C) 2005 Elsevier B.V. All rights reserved.

}, keywords = {diamond film, hot filament CVD, morphology transitions, nitrogen}, issn = {0925-9635}, doi = {10.1016/j.diamond.2004.11.042}, author = {Kshirsagar, S. T. and Kshirsagar, R. B. and Patil, P. S. and Kulkarni, A. and Mandate, A. B. and Gaikwad, A. B. and Gokhale, Suresh P.} } @article { ISI:000232341900001, title = {Surface disorder in c-Si induced by swift heavy ions}, journal = {Radiation Effects and Defects in Solids}, volume = {160}, number = {6}, year = {2005}, month = {JUN}, pages = {207-218}, publisher = {TAYLOR \& FRANCIS LTD}, address = {4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND}, abstract = {

The disorders induced in crystalline silicon (c-Si) through the process of electronic energy loss in the swift heavy ion irradiation were investigated. A number of silicon \<100\> samples were irradiated with 65 MeV oxygen ions at different fluences, 1x10(13) to 1.5x10(14) ions/cm(2), and characterized by the Raman spectroscopy, the optical reflectivity, the X-ray reflectivity, the atomic force microscopy (AFM) and the X-ray diffraction (XRD) techniques. The intensity, redshift, phonon coherence length and asymmetric broadening associated with the Raman peaks reveal that stressed and disordered lattice zones are produced in the surface region of the irradiated silicon. The average crystallite size, obtained by analyzing Raman spectrum with the phonon confinement model, was very large in the virgin silicon but decreased to \<100 nm dimension in the ion irradiated silicon. The results of the X-ray reflectivity, AFM and optical reflectivity of 200-700 nm radiation indicate that the roughness of the silicon surface has enhanced substantially after ion irradiation. The diffusion of oxygen in silicon surface during ion irradiation is evident from the oscillation in the X-ray reflectivity spectrum and the sharp decrease in the reflectivity of 200-400 nm radiation. The rise in temperature, estimated from the heat spike model, was high enough to melt the local silicon surface. The results of XRD indicate that lattice defects have been induced and a new plane \<211\> has been formed in the silicon \<100\> after ion irradiation. The results of the present study show that the energy deposited in crystalline silicon through the process of electronic energy loss similar to 0.944 keV/nm per ion is sufficient to induce disorders of appreciable magnitude in the silicon surface even at a fluence of similar to 10(13) ions/cm(2).

}, keywords = {AFM, crystalline silicon, ion irradiation, optical and X-ray reflectivity, Raman, XRD}, issn = {1042-0150}, doi = {10.1080/10420150500275288}, author = {Bogle, Kashinath A. and Gokhale, Suresh P. and Bhoraskar, Vasant N.} } @article { ISI:000235439900024, title = {Low temperature route to prepare LaMnO3}, journal = {Materials Letters}, volume = {60}, number = {9-10}, year = {2006}, month = {MAY}, pages = {1213-1214}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A combination of digestion and further low temperature calcination to crystallize the product is employed to prepare LaMnO3(LM) ceramics. Freshly co-precipitated lanthanum and manganese hydroxides gel is allowed to react at 100 degrees C under refluxing and stirring conditions for 6-12 h. The X-ray amorphous product so formed is heated at 300 degrees C to form crystalline LM powders. This is the lowest temperature so far reported for the formation of LaMnO3. Transmission electron microscope (TEM) investigations revealed that the average particle size is 50 nm for the calcined powders. (c) 2005 Elsevier B.V All rights reserved.

}, keywords = {Chemical synthesis, LaMnO3, Precipitation, transmission electron microscopy, X-ray diffraction}, issn = {0167-577X}, doi = {10.1016/j.matlet.2005.11.002}, author = {Daundkar, A. and Kale, Sangeeta N. and Gokhale, Suresh P. and Ravi, V} } @article { ISI:000252408000048, title = {Synthesis of LSMO at low temperature by novel hydroxide precursor technique}, journal = {Materials Letters}, volume = {62}, number = {3}, year = {2008}, month = {FEB}, pages = {527-529}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A novel technique of mixing individual hydroxide is employed to prepare La0.65Sr0.35MnO3 (LSMO) at low temperature. Freshly prepared lanthanum and manganese hydroxides are mixed thoroughly with strontium hydroxide in stoichiometric ratio and heated at different temperatures ranging from 100 to 500 degrees C for 6 h. At 500 degrees C, formation of La0.65Sr0.35MnO3 was confirmed by the X-ray diffraction studies (XRD). This is the lowest temperature so far reported in the literature. The particle size and morphology were investigated by scanning electron microscopy (SEM). (c) 2007 Elsevier B.V. All rights reserved.

}, keywords = {Ceramics, Electron microscopy, La0.65Sr0.35MnO3, Oxides, Precipitation, X-ray diffraction}, issn = {0167-577X}, doi = {10.1016/j.matlet.2007.05.077}, author = {Gupta, U. N. and Muthurajan, H. and Kumar, H. H. and Rao, N. Koteswara and Gokhale, Suresh P. and Ravi, V.} } @article { ISI:000275363900023, title = {Fabrication, characterization and electrochemical performance of single strand carbon fiber prepared by catalytic chemical vapor decomposition method}, journal = {Electrochimica Acta}, volume = {55}, number = {6}, year = {2010}, month = {FEB}, pages = {2022-2028}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Preparation, fabrication and voltammetric characterizations of a single strand of carbon fiber (SSCF) electrode and their potential applications for biosensor are presented. SSCFs of diameter ca. 10 +/- 2 mu m and few millimeters in length are prepared by catalytic chemical vapor decomposition (CCVD) method. Voltammetry with potassium ferricyanide. alpha-methylferrocene methanol and hexaammineruthenium(III) chloride on SSCF electrode are used as bench marks to validate the electrode properties. Quasi-steady state voltammograms obtained were fitted into a cylindrical diffusion model From which, the standard rate constant (k(0)) and electron transfer coefficient (alpha) are obtained. The use of SSCF electrode is demonstrated for the voltammetric detection of the micromolar quantity of dopamine in the presence of large excess (ca. 200 times) of ascorbic acid, without any fouling of electrode surface. The kinetics of electron transfer are investigated. (C) 2009 Elsevier Ltd All rights reserved.

}, keywords = {alpha-Methylferrocene methanol, Ascorbic acid, Catalytic chemical vapor decomposition (CCVD), Cylindrical diffusion, dopamine, Hexaammineruthenium(III) chloride, Single strand carbon fiber (SSCF) electrode}, issn = {0013-4686}, doi = {10.1016/j.electacta.2009.11.025}, author = {Joshi, Vrushali S. and Gokhale, Suresh P. and Patil, Kashinath R. and Haram, Santosh K.} } @article { ISI:000280359700010, title = {Pd-functionalized carbon nanotubes for selective hydrogenation of 2-butyne-1,4-diol}, journal = {Advanced Science Letters}, volume = {3}, number = {3}, year = {2010}, month = {SEP}, pages = {313-318}, publisher = {AMER SCIENTIFIC PUBLISHERS}, address = {26650 THE OLD RD, STE 208, VALENCIA, CA 91381-0751 USA}, abstract = {

Multiwalled carbon nanotubes were prepared by thermal decomposition method followed by acid treatment and Pd-functionalization with PdCl2 by wet impregnation method. The Pd functionlized carbon nanotubes catalyst was characterized by BET, FT-IR, Raman, XRD, EDX, ICP-OES, SEM and TEM and was evaluated for its activity for hydrogenation of 2-butyne-1,4-diol. It showed higher selectivity (93\%) to 2-butene-1,4-diol than Pd supported on commercial carbon (70\% selectivity to 2-butene-1,4-diol) for complete conversion of 2-butyne-1,4-diol. The catalyst also exhibited excellent stability as evidenced by the three catalyst recycle experiments.

}, issn = {1936-6612}, doi = {10.1166/asl.2010.1128}, author = {Nadgeri, Jayprakash M. and Garade, Ajit C. and Tambe, Romana A. and Gokhale, Suresh P. and Rode, Chandrashekhar V.} } @article { ISI:000300185800011, title = {Enhancing the hydrogen storage capacity of Pd-functionalized multi-walled carbon nanotubes}, journal = {Applied Surface Science}, volume = {258}, number = {8}, year = {2012}, month = {FEB}, pages = {3405-3409}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

We demonstrate that the hydrogen storage capacity of multi-walled carbon nanotubes can be enhanced by polyvinylpyrrolidone functionalization. The polyvinylpyrrolidone acts as a stabilizing agent for Pd-nanoparticles, reduces their size and facilitates their uniform and enhanced loading onto multi-walled carbon nanotubes. According to sorption studies, the polyvinylpyrrolidone capping and consequent nanostructural modification enables 2.3 times more hydrogen adsorption than mere Pd-functionalization of multi-walled carbon nanotubes. Corresponding morphological changes before and after polyvinylpyrrolidone capping, characterized using Raman Spectroscopy, X-ray diffraction, TEM and thermal analysis techniques, are also presented. The results contribute towards increasing the efficiency of hydrogen based sustainable energy sources. (C) 2011 Elsevier B.V. All rights reserved.

}, keywords = {Hydrogen based energy sources, Hydrogen storage capacity, Multiwalled carbon nanotubes, Pd functionalization, PVP capping}, issn = {0169-4332}, doi = {10.1016/j.apsusc.2011.11.075}, author = {Singh, Priyanka and Kulkarni, Mukta V. and Gokhale, Suresh P. and Chikkali, Samir H. and Kulkarni, Chandrashekhar V.} } @article { ISI:000316024500022, title = {Synthesis of low coercive BaFe12O19 hexaferrite for microwave applications in low-temperature cofired ceramic}, journal = {Journal of Electronic Materials}, volume = {42}, number = {4}, year = {2013}, month = {APR}, pages = {761-768}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Polycrystalline M-type barium hexaferrite (BaFe12O19) samples have been synthesized by solution combustion route at different pH and calcination conditions in order to reduce the coercivity for microwave applications in low-temperature cofired ceramic (LTCC) substrates. Structural, morphological, and magnetic properties of BaFe12O19 were studied by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Raman spectroscopy, vibrating sample magnetometry (VSM), and Mossbauer spectroscopy. The formation of a single-phase hexagonal structure was confirmed by XRD. The Raman spectra reveal all characteristic peaks of BaFe12O19, illustrating the phase purity and crystal lattice symmetry of the synthesized material. Mossbauer spectra illustrate the existence of Fe3+ cations at all five crystallographic lattice sites. The microstructural features observed by FESEM disclose the growth of nanoregime particles into hexagonal platelet particles after calcination at temperatures from 800A degrees C to 1200A degrees C. The VSM results show a lower coercivity (1350 Oe to 3500 Oe) together with reasonably high saturation magnetization (55 emu/g to 60 emu/g) and a high bulk resistivity (\> 10(9) Omega-cm) at room temperature. The dependence of magnetic and electrical properties on the preparation and processing conditions is also discussed.

}, keywords = {Barium hexaferrite, coercivity, LTCC, Mossbauer spectroscopy, Raman spectroscopy}, issn = {0361-5235}, doi = {10.1007/s11664-012-2398-6}, author = {Rane, Vivek A. and Meena, Sher Singh and Gokhale, Suresh P. and Yusuf, S. M. and Phatak, Girish J. and Date, Sadgopal K.} }