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Nayak S.,Academy of Scientific and Innovative Research | Nayak S.,CSIR - Institute of Minerals And Materials Technology | Nayak S.,Gujarat Energy Research and Management Institute Research | Bhattacharjee S.,Academy of Scientific and Innovative Research | And 2 more authors.
Advances in Natural Sciences: Nanoscience and Nanotechnology | Year: 2014

Presence of acidic, basic and neutral additives on dispersion of multiwalled carbon nanotubes (MWCNTs) in dimethylforamide (DMF) solution has been investigated. The surface charge measurement showed that MWCNTs in the presence of acidic additives in DMF exhibit a higher surface charge (-85 C g-1) than that with the basic additives (-22 C g-1 ). The stability of the MWCNTs dispersion was visually monitored and it was found that in the presence of acidic and no additives it would be stable and dispersed for more than five days, whereas MWCNTs suspension immediately settle down in the presence of basic and neutral additives. The degree of defects on MWCNTs was determined by analysis of detailed Raman spectra of as-received MWNCTs and MWNCTs dispersed in DMF with different additives. By exploring the correlation between the ID/ IG (Raman analysis) ratio and the degree of defects, it was found that the carbon-carbon double bond (C=C) of MWCNTs was slightly damaged by adding additives to the solvent. © 2014 Vietnam Academy of Science & Technology Source


Nayak S.,Academy of Scientific and Innovative ResearchNew Delhi110001 India | Behura S.K.,Gujarat Energy Research and Management Institute Research | Bhattacharjee S.,Academy of Scientific and Innovative ResearchNew Delhi110001 India
Polymer Composites | Year: 2015

Mechanically robust and flexible polymer-multiwall carbon nanotubes (MWCNT) composites are developed by in situ polymerization technique, where MWCNT are embedded in nontoxic, bio-compatible acryl amide-based polymer matrix. The addition of glycerol in the composite imparts required flexibility and a further addition of poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) shows significant improvements in tensile modulus, strength, and toughness compared to the polymer matrix. The composite is characterized by Scanning electron microscopy, Raman spectroscopy Attenuated total reflectance Fourier Transform infrared spectroscopy. At optimized conditions; the composite forms a heterojunction diode with n-Silicon having an electronic rectification ratio of 2.11 at ±1 V and a further addition of conducting polymer PEDOT: PSS in the composite enhances the electronic current rectification to 13.63 at ±1 V, with the turn on voltage of the device at 0.35 V. © 2015 Society of Plastics Engineers. Source


Behura S.K.,Gujarat Energy Research and Management Institute Research | Behura S.K.,Pandit Deendayal Petroleum University | Mahala P.,Pandit Deendayal Petroleum University | Nayak S.,Gujarat Energy Research and Management Institute Research | And 3 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2014

High quality graphene film is fabricated using mechanical exfoliation of highly-oriented pyrolytic graphite. The graphene films on glass substrates are characterized using field-emission scanning electron microscopy, atomic force microscopy, Raman spectroscopy, UV-vis spectroscopy and Fourier transform infrared spectroscopy. A very high intensity ratio of 2D to G-band (≈1.67) and narrow 2D-band full-width at half maximum (≈40 cm-1) correspond to the bi-layer graphene formation. The bi-layer graphene/p-GaN/n- InGaN/n-GaN/GaN/sAl2O3 system is studied theoretically using TCAD Silvaco software, in which the properties of exfoliated bi-layer graphene are used as transparent and conductive film, and the device exhibits an efficiency of 15.24% compared to 13.63% for ITO/p-GaN/n-InGaN/n-GaN/GaN/Al 2O3 system. Copyright © 2014 American Scientific Publishers. Source


Behura S.K.,University of Saskatchewan | Behura S.K.,Gujarat Energy Research and Management Institute Research | Yang Q.,University of Saskatchewan | Hirose A.,University of Saskatchewan | And 2 more authors.
Journal of Materials Science | Year: 2014

A new process has been developed to grow silicon (Si) nanowires (NWs), and their growth mechanisms were explored and discussed. In this process, SiNWs were synthesized by simply oxidizing and then reducing Si wafers in a high temperature furnace. The process involves H2, in an inert atmosphere, reacts with thermally grown SiO2 on Si at 1100 C enhancing the growth of SiNWs directly on Si wafers. High-resolution transmission electron microscopy studies show that the NWs consists of a crystalline core of ~25 nm in diameter and an amorphous oxide shell of ~2 nm in thickness, which was also supported by selected area electron diffraction patterns. The NWs synthesized exhibit a high aspect ratio of ~167 and room temperature phonon confinement effect. This simple and economical process to synthesize crystalline SiNWs opens up a new way for large scale applications. © 2014 Springer Science+Business Media New York. Source


Batra K.,Gujarat Energy Research and Management Institute Research | Batra K.,IndiaInstitute of Technology | Nayak S.,Gujarat Energy Research and Management Institute Research | Behura S.K.,Gujarat Energy Research and Management Institute Research | Jani O.,Gujarat Energy Research and Management Institute Research
Journal of Nanoscience and Nanotechnology | Year: 2015

Chemically-derived graphene have been synthesized by modified Hummers method and reduced using sodium borohydride. To explore the potential for photovoltaic applications, graphene/p-silicon (Si) heterojunction devices were fabricated using a simple and cost effective technique called spin coating. The SEM analysis shows the formation of graphene oxide (GO) flakes which become smooth after reduction. The absence of oxygen containing functional groups, as observed in FT-IR spectra, reveals the reduction of GO, i.e., reduced graphene oxide (rGO). It was further confirmed by Raman analysis, which shows slight reduction in G-band intensity with respect to D -band. Hall effect measurement confirmed n -type nature of rGO. Therefore, an effort has been made to simulate rGO/p-Si heterojunction device by using the one-dimensional solar cell capacitance software, considering the experimentally derived parameters. The detail analysis of the effects of Si thickness, graphene thickness and temperature on the performance of the device has been presented. © 2015 American Scientific Publishers All rights reserved Printed in the United States of America. Source

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