02243nas a2200217   4500008004100000022001400041245009100055210006900146260008000215300001400295490000700309520146900316100002101785700002001806700001701826700001301843700001801856700002201874700001601896856011301912       2006                        eng d  a0957-448400aEffect of a focusing electric field on the formation of arc generated carbon nanotubes0 aEffect of a focusing electric field on the formation of arc gene  aDIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLANDbIOP PUBLISHING LTDcDEC  a5895-59020 v173 a<p>The effect of a focusing electric field on the formation of carbon nanotubes in a direct current arc-plasma is investigated. The hard deposits on the surface of the cathode are the main products, rich in multi-walled carbon nanotubes. It is seen that the focusing electric field has a distinct influence on the yield, purity and morphology of the nanotubes. The yield of the carbon nanotubes under the `focused field condition' has been found to be higher than that derived from the normal electrode configuration. It has been observed that the deposition of carbonaceous soot on the reactor wall is considerably reduced on application of the focusing electric field. Transmission electron microscopy has been used to determine the morphology of the nanotubes. In addition, Raman spectroscopy has helped in distinguishing the graphene-like structures from the disordered carbon networks and helped in analysing the morphology of the tubes. Thermal analysis gave a qualitative estimation of the relative yield of carbon nanotubes within the cathode deposits and their thermal stabilities. The crystalline nature of the samples has been confirmed by x-ray diffraction analysis. The results clearly indicate that the focusing electric field confines the positively charged carbon precursors within the cathode-anode space causing high relative yield and purity and has a distinct effect on controlling the inner diameter of the as-synthesized carbon nanotubes.</p>1 aKarmakar, Soumen1 aNagar, Harshada1 aPasricha, R.1 aSeth, T.1 aSathe, V., G.1 aBhoraskar, S., V.1 aDas, A., K.  uhttps://library.ncl.res.in/content/effect-focusing-electric-field-formation-arc-generated-carbon-nanotubes-002788nas a2200325   4500008004100000022001400041245010500055210006900160260008700229300001400316490000800330520170300338653001002041653002402051653002002075653001502095653002702110653002202137653000902159100001702168700001802185700001702203700002202220700001802242700001902260700001602279700002202295700002202317856012302339       2010                        eng d  a0040-609000aEffect of leakage current and dielectric constant on single and double layer oxides in MOS structure0 aEffect of leakage current and dielectric constant on single and   aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbAmer Vacuum Soc, Adv Surface Engn DivcDEC  a1530-15350 v5193 a<p>MOS structure of Al/Al2O3/n-Si, Al/TiO2/n-Si and Al/Al2O3/TiO2/n-Si was obtained by deposition of Al2O3 and TiO2 on silicon substrate by RF Magnetron Sputtering system. The total thickness of the oxide layer similar to 40 +/- 5 nm in the MOS structure was kept constant. Samples were characterized by X-Ray diffraction (XRD). X-Ray photoelectron spectroscopy (XPS), Impedance analyzer and Current-voltage (J-V) characteristics. The variations in the dielectric constant and tan 8 of the MOS capacitor in the frequency range of 1000Hz-1MHz were measured by impedance analyzer. The variation in dielectric constant of the Al/Al2O3/TiO2/n-Si multilayer compared to single layer of Al/Al2O3/n-Si and Al/TiO2/n-Si is due to high probability of defects, lattice mismatch and interface interactions. The steep rise of Tan 6 values in the Al/Al2O3/TiO2/n-Si structure is due to the resonance effect of both Al2O3 and TiO2 layers. The leakage current mechanisms of MOS structures were extracted from Schottky coefficient and Poole-Frenkel coefficient. Theoretical values of Schottky coefficients (beta(SC)) and Poole-Frenkel coefficients (beta(PF)) for each sample were estimated using the real part of the dielectric constant. The experimental values were calculated from J-V characteristics and compared with theoretical values. The appropriate model has been proposed. It was found that Schottky and Poole-Frenkel mechanisms are applicable at low and high field respectively for all MOS structures. The combination of Al/Al2O3/TiO2/n-Si is found to be a promising structure with high dielectric constant and low leakage current suitable for MOS devices. (C) 2010 Elsevier B.V. All rights reserved.</p>10aAl2O310adielectric constant10aLeakage current10aMOS device10aPoole-Frenkel emission10aSchottky emission10aTiO21 aLaha, Pinaki1 aPanda, A., B.1 aDahiwale, S.1 aDate, Kalyani, S.1 aPatil, K., R.1 aBarhai, P., K.1 aDas, A., K.1 aBanerjee, Indrani1 aMahapatra, S., K.  uhttps://library.ncl.res.in/content/effect-leakage-current-and-dielectric-constant-single-and-double-layer-oxides-mos-0