@article {43230, title = {Enhanced field-emission behavior of layered MoS2 sheets}, journal = {Small}, volume = {9}, year = {2013}, month = {AUG}, pages = {2730-2734}, abstract = {Field emission studies are reported for the first time on layered MoS2 sheets at the base pressure of approximate to 1 x 10(-8) mbar. The turn-on field required to draw a field emission current density of 10 A/cm(2) is found to be 3.5 V/m for MoS2 sheets. The turn-on values are found to be significantly lower than the reported MoS2 nanoflowers, graphene, and carbon nanotube-based field emitters due to the high field enhancement factor (approximate to 1138) associated with nanometric sharp edges of MoS2 sheet emitter surface. The emission current-time plots show good stability over a period of 3 h. Owing to the low turn-on field and planar (sheetlike) structure, the MoS2 could be utilized for future vacuum microelectronics/nanoelectronic and flat panel display applications.}, doi = {10.1002/smll.201300002}, author = {Kashid, Ranjit V. and Late, Dattatray J. and Chou, Stanley S. and Huang, Yi-Kai and De, Mrinmoy and Joag, Dilip S. and More, Mahendra A. and Dravid, Vinayak P.} } @article { ISI:000322587800006, title = {High efficiency electron field emission from protruded graphene oxide nanosheets supported on sharp silicon nanowires}, journal = {Journal of Materials Chemistry C}, volume = {1}, number = {33}, year = {2013}, month = {JUN}, pages = {5040-5046}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Graphene oxide (GO) potentially has applications in vacuum microelectronic devices for realization of field emission displays. Graphene and its derivatives are expected to be efficient field emitters due to their unique electrical properties. However, the flat sheet structure of graphene or GO allows electron field emission only from the edges of graphene and GO nanosheets. In order to extract maximum field emission current density at lower applied voltage from the GO nanosheets, we supported and stretched them on sharp tips of silicon nanowires (SiNWs). Highly efficient and stable field emission with low turn-on field was observed for these SiNW-GO heterostructures. The sharp protrusions created by stretching of the GO nanosheets on SiNWs locally enhance the electric field and thus enhance the field emission characteristics. The dominant use of silicon in electronic devices makes this approach robust for the development of field emission devices using graphene based field emitters.

}, issn = {2050-7526}, doi = {10.1039/c3tc30904e}, author = {Devarapalli, Rami Reddy and Kashid, Ranjit V. and Deshmukh, Ashvini B. and Sharma, Ponchami and Das, Manash R. and More, Mahendra A. and Shelke, Manjusha V.} } @article { ISI:000327521300003, title = {Superior field emission properties of layered WS2-RGO nanocomposites}, journal = {Scientific Reports}, volume = {3}, year = {2013}, month = {NOV}, pages = {3282}, publisher = {NATURE PUBLISHING GROUP}, address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND}, abstract = {

We report here the field emission studies of a layered WS2-RGO composite at the base pressure of similar to 1 x 10(-8) mbar. The turn on field required to draw a field emission current density of 1 mu A/cm(2) is found to be 3.5, 2.3 and 2 V/mu m for WS2, RGO and the WS2-RGO composite respectively. The enhanced field emission behavior observed for the WS2-RGO nanocomposite is attributed to a high field enhancement factor of 2978, which is associated with the surface protrusions of the single-to-few layer thick sheets of the nanocomposite. The highest current density of similar to 800 mu A/cm(2) is drawn at an applied field of 4.1 V/mu m from a few layers of the WS2-RGO nanocomposite. Furthermore, first-principles density functional calculations suggest that the enhanced field emission may also be due to an overalp of the electronic structures of WS2 and RGO, where graphene-like states are dumped in the region of the WS2 fundamental gap.

}, issn = {2045-2322}, doi = {10.1038/srep03282}, author = {Rout, Chandra Sekhar and Joshi, Padmashree D. and Kashid, Ranjit V. and Joag, Dilip S. and More, Mahendra A. and Simbeck, Adam J. and Washington, Morris and Nayak, Saroj K. and Late, Dattatray J.} } @article { ISI:000330143000008, title = {CdS nanowires: ultra-long growth and enhanced field emission properties}, journal = {Vaccum}, volume = {101}, number = {SI}, year = {2014}, month = {MAR}, pages = {38-45}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Here, we report the synthesis of ultra-long CdS nanowires with aspect ratio similar to 8 x 10(4) by simple route of thermal evaporation technique. A change in the vertical arrangement of quartz boats leads in to the synthesis of ultra-long CdS nanovvires via high degree of condensation. This technique is seen to be cost effective and easy. The growth of the nanowires is found to be increased very rapidly from few micrometers to few millimeters. The possible reason for the growth of the ultra-long CdS nanowires is discussed in detail. The turn-on field defined for the current density of similar to 0.1 mu A/cm(2) has been found to be similar to 1.4, 1.45, 1 and 0.17 V/mu m for specimen A, B, C and D (specimens A-D, synthesized by variation in synthesis parameters) respectively. The turn-on field of the specimen D (similar to 0.17 V/mu m) is found to be quite superior than the value reported for other CdS nanoforms which is very remarkable. Simple way of bulk fabrication leads to the low turn-on value which indicates a possible use of the present emitter in the micro/nanoelectronics devices. (C) 2013 Elsevier Ltd. All rights reserved.

}, keywords = {Current stability, field emission, synthesis}, issn = {0042-207X}, doi = {10.1016/j.vacuum.2013.07.019}, author = {Chavan, Padmakar G. and Kashid, Ranjit V. and Badhade, Satish S. and Mulla, Imtiaz S. and More, Mahendra A. and Joag, Dilip S.} } @article { ISI:000341152600073, title = {Enhanced field emission properties of doped graphene nanosheets with layered SnS2}, journal = {Applied Physics Letters}, volume = {105}, number = {4}, year = {2014}, month = {JUL}, pages = {043109}, publisher = {AMER INST PHYSICS}, address = {CIRCULATION \& FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA}, abstract = {

We report here our experimental investigations on p-doped graphene using tin sulfide (SnS2), which shows enhanced field emission properties. The turn on field required to draw an emission current density of 1 mu A/cm(2) is significantly low (almost half the value) for the SnS2/reduced graphene oxide (RGO) nanocomposite (2.65 V/mu m) compared to pristine SnS2 (4.8 V/mu m) nanosheets. The field enhancement factor beta (similar to 3200 for the SnS2 and similar to 3700 for SnS2/RGO composite) was calculated from Fowler-Nordheim (F-N) plots, which indicates that the emission is from the nanometric geometry of the emitter. The field emission current versus time plot shows overall good emission stability for the SnS2/RGO emitter. The magnitude of work function of SnS2 and a SnS2/graphene composite has been calculated from first principles density functional theory (DFT) and is found to be 6.89 eV and 5.42 eV, respectively. The DFT calculations clearly reveal that the enhanced field emission properties of SnS2/RGO are due to a substantial lowering of the work function of SnS2 when supported by graphene, which is in response to p-type doping of graphene. (C) 2014 AIP Publishing LLC.

}, issn = {0003-6951}, doi = {10.1063/1.4892001}, author = {Rout, Chandra Sekhar and Joshi, Padmashree D. and Kashid, Ranjit V. and Joag, Dilip S. and More, Mahendra A. and Simbeck, Adam J. and Washington, Morris and Nayak, Saroj K. and Late, Dattatray J.} } @article { ISI:000344791100009, title = {Metallic few-layer flowerlike VS2 nanosheets as field emitters}, journal = {European Journal of Inorganic Chemistry}, number = {31}, year = {2014}, month = {NOV}, pages = {5331-5336}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

We report first-principles DFT calculations of the single-layer VS2 work function, the experimental synthesis of flower-like few-layer-thick VS2 nanosheets by a simple one-step hydrothermal method, and the investigation of their field emission properties. The turn-on field required to draw emission current densities of 1 and 10 mu A/cm(2) were 4 and 5.01 V/mu m, respectively. The observed turn-on field values are attributed to the high field enhancement factor (ca. 2500), which is due to presence of sharp protrusions in the VS2 nanosheets. Furthermore, the field-emission current stability of the VS2 emitter shows stable behavior over a period of 12 h. Further, DFT calculations show that the work function (f) of the single-layer VS2 emitter is 6.01 eV.

}, keywords = {Density functional calculations, field emission, Layered compounds, Nanostructures, Sulfur, Vanadium}, issn = {1434-1948}, doi = {10.1002/ejic.201402448}, author = {Rout, Chandra Sekhar and Khare, Ruchita T. and Kashid, Ranjit V. and Joag, Dilip S. and More, Mahendra A. and Lanzillo, Nicholas A. and Washington, Morris and Nayak, Saroj K. and Late, Dattatray J.} } @article { ISI:000342328300031, title = {Pulsed laser-deposited MoS2 thin films on W and Si: field emission and photoresponse studies}, journal = {ACS Applied Materials \& Interfaces}, volume = {6}, number = {18}, year = {2014}, month = {SEP}, pages = {15881-15888}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

We report field electron emission investigations on pulsed laser-deposited molybdenum disulfide (MoS2) thin films on W-tip and Si substrates. In both cases, under the chosen growth conditions, the dry process of pulsed laser deposition (PLD) is seen to render a dense nanostructured morphology of MoS2, which is important for local electric field enhancement in field emission application. In the case of the MoS2 film on silicon (Si), the turn-on field required to draw an emission current density of 10 mu A/cm(2) is found to be 2.8 V/mu m. Interestingly, the MoS2 film on a tungsten (W) tip emitter delivers a large emission current density of similar to 30 mA/cm(2) at a relatively lower applied voltage of similar to 3.8 kV. Thus, the PLD-MoS2 can be utilized for various field emission-based applications. We also report our results of photodiode-like behavior in (n- and p- type) Si/PLDMoS2 heterostructures. Finally we show that MoS2 films deposited on flexible kapton substrate show a good photoresponse and recovery. Our investigations thus hold great promise for the development of PLD MoS2 films in application domains such as field emitters and heterostructures for novel nanoelectronic devices.

}, keywords = {field emission, MoS2, photodiode heterostructures, pulsed laser deposition, thin film}, issn = {1944-8244}, doi = {10.1021/am503464h}, author = {Late, Dattatray J. and Shaikh, Parvez A. and Khare, Ruchita T. and Kashid, Ranjit V. and Chaudhary, Minakshi V. and More, Mahendra A. and Ogale, Satishchandra B.} } @article { ISI:000332619100046, title = {Temperature dependent Raman spectroscopy of chemically derived few layer MoS2 and WS2 nanosheets}, journal = {Applied Physics Letters}, volume = {104}, number = {8}, year = {2014}, month = {FEB}, pages = {081911}, publisher = {AMER INST PHYSICS}, address = {1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA}, abstract = {We have systematically investigated the temperature dependent Raman spectroscopy behavior of a few layered MoS2 and WS2 nanosheets synthesized using simple hydrothermal method. Our result reveals A(1g) and E-2g(1) modes soften as temperature increases from 77 K to 623 K. This behavior can be explained in terms of a double resonance process which is active in single-and few layer thick nanosheets. The frequency shifts and peak broadening can provide unambiguous, nondestructive, and accurate information of a few layered MoS2 and WS2. This mechanism can also be applicable in characterizing the structural, optical, electronic, and vibrational properties of other emerging layered materials. (c) 2014 AIP Publishing LLC.}, issn = {0003-6951}, doi = {10.1063/1.4866782}, author = {Thripuranthaka, M. and Kashid, Ranjit V. and Rout, Chandra Sekhar and Late, Dattatray J.} } @article { ISI:000334078500086, title = {Temperature dependent Raman spectroscopy of chemically derived few layer MoS2 and WS2 nanosheets (vol 104, 081911, 2014)}, journal = {Applied Physics Letters}, volume = {104}, number = {12}, year = {2014}, month = {MAR}, pages = {129901}, publisher = {AMER INST PHYSICS}, address = {CIRCULATION \& FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA}, issn = {0003-6951}, doi = {10.1063/1.4869463}, author = {Thripuranthaka, M. and Kashid, Ranjit V. and Rout, Chandra Sekhar and Late, Dattatray J.} } @article { ISI:000354067400001, title = {Stable field emission from layered MoS2 nanosheets in high vacuum and observation of 1/f noise}, journal = {Nanomaterials and Nanotechnology}, volume = {5}, year = {2015}, month = {APR}, pages = {10}, publisher = {INTECH EUROPE}, address = {JANEZA TRDINE 9, RIJEKA, 51000, CROATIA}, abstract = {

Field emission and current noise of hydrothermally synthesized MoS2 nanosheets are investigated in ultra-high-vacuum and industrially suited high-vacuum conditions. The study reveals that the emission turn-on field is pressure dependent. Moreover, the MoS2 nanosheets exhibit more stable field-electron emission in high-vacuum than in ultra-high-vacuum conditions. The investigations on field-emission current fluctuations show features of 1/f-type noise in ultra-high-vacuum and high-vacuum conditions, attributed to adsorption and desorption processes. The post-field-emission results indicate the MoS2 nanosheets are a robust field emitter in high-vacuum conditions.

}, keywords = {Electron emission, layered materials, MoS2, Noise measurement, Raman spectroscopy}, issn = {1847-9804}, doi = {10.5772/60071}, author = {Kashid, Ranjit V. and Joag, Pracheetee D. and Thripuranthaka, M. and Rout, Chandra S. and Late, Dattatray J. and More, Mahendra A.} }