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Umber Kalsoom, M. Shahid Rafique, Shamaila Shahzadi, Khizra Fatima and Rabia ShaheeN

Abstract

The objective of the present research work is to optimize the growth conditions of bi- tri- and few-layer graphene using pulsed laser deposition (PLD) technique. The graphene was grown on n-type silicon (1 0 0) at 530 °C. Raman spectroscopy of the grown films revealed that the growth of low defect tri-layer graphene depended upon Ni content and uniformity of the Ni film. The line profile analysis of the AFM micrographs of the films also confirmed the formation of bi- tri- and a few-layer graphene. The deposited uniform Ni film matrix and carbon/Ni thickness ratio are the controlling factors for the growth of bitri- or few- layer graphene using pulsed laser deposition technique.

Open access

Sun Chuanyu and Wang Yu

Abstract

In the paper, a magnetic composite of graphene oxide (MGO) has been successfully synthesized through decomposition of iron (III) acetylacetonate in the mixture solution of triethylene glycol and graphene oxide (GO). Atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and superconducting quantum interference device were used to characterize the material. The results show that the magnetic Fe3O4 nanoparticles modified graphene oxide composite with superparamagnetic properties, and magnetization saturation of 16.4 emu/g has been obtained. The MGO has a good sustained-release performance, and in vitro cytotoxicity confirming its secure use as a potential drug carrier.

Open access

Jozef Liday, Peter Vogrinčič, Viliam Vretenár, Mário Kotlár, Marián Marton and Vlastimil Řeháček

Abstract

Due to their properties, carbon nanotubes and reduced graphene oxide are highly promising materials for obtaining low-resistance ohmic contacts to p-GaN with good optical transparency for visible light. In this contribution we designed a combination of these two materials, along with a cap layer, to be used as structures for ohmic contacts to p-GaN. Carbon nanotube (CNT) and graphene oxide (GO) layers were deposited by spray coating using an off-the-shelf airbrush on p-GaN layers. The metallic layers of Au/Pd were vapour deposited. The structures for ohmic contacts were prepared in two configurations, namely as Au/Pd/r-GO/CNT/p-GaN and Au/Pd/CNT/r-GO/CNT/p-GaN. The prepared structures provide a low resistivity ohmic contact after subsequent annealing in air ambient at 600 °C for 3 minutes. The contact containing the sandwich CNT/r-GO/CNT interstructure exhibits lower values of contact resistance in comparison with the r-GO/CNT interstructure.

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Lukasz Jarosinski, Andrzej Rybak, Karolina Gaska, Grzegorz Kmita, Renata Porebska and Czeslaw Kapusta

Abstract

Efficient heat dissipation from modern electronic devices is a key issue for their proper performance. An important role in the assembly of electronic devices is played by polymers, due to their simple application and easiness of processing. The thermal conductivity of pure polymers is relatively low and addition of thermally conductive particles into polymer matrix is the method to enhance the overall thermal conductivity of the composite. The aim of the presented work is to examine a possibility of increasing the thermal conductivity of the filled epoxy resin systems, applicable for electrical insulation, by the use of composites filled with graphene nanoplatelets. It is remarkable that the addition of only 4 wt.% of graphene could lead to 132 % increase in thermal conductivity. In this study, several new aspects of graphene composites such as sedimentation effects or temperature dependence of thermal conductivity have been presented. The thermal conductivity results were also compared with the newest model. The obtained results show potential for application of the graphene nanocomposites for electrical insulation with enhanced thermal conductivity. This paper also presents and discusses the unique temperature dependencies of thermal conductivity in a wide temperature range, significant for full understanding thermal transport mechanisms.

Open access

Khaled M. Elsabawy

1 Introduction It is well known that graphene is a flat monolayer of carbon atoms tightly packed into a two-dimensional honeycomb lattice, forming the basic building block for all carbon nanostructures [ 1 ]. Graphene showns many intriguing properties which makes it one of the most promising materials in the next decades [ 2 , 3 ]. In 2004, Novoselov et al. [ 4 ] developed a micromechanical exfoliation method that consisted of repeated peeling of graphite flakes, using adhesive tape until the thinnest flakes were obtained, which were then transferred

Open access

Sylwia M. Krzemińska, Aleksandra A. Smejda-Krzewicka and Andrzej Leniart

LITERATURE CITED 1. Gołębiewski, J. (2004). Polymer nanocomposites. Structure, methods of preparation and properties. Przem. Chem . 83 (1), 15–20. 2. Alexandre, M. & Dubois, P. (2000). Polymer-layered silicate nanocomposites: Preparation, properties and uses of a new class of materials. Mater. Sci. Eng. R. Rep. 28(1–2), 1–63. DOI: 10.1016/S0927-796X(00)00012-7. 3. Sadasivuni, K.K., Ponnamma, D., Thomas, S. & Grohens, Y. (2014). Evolution from graphite to graphene elastomer composites. Prog. Polym. Sci. 39(4), 749–780. DOI: 10.1016/j

Open access

Kamil Kornaus, Agnieszka Gubernat, Dariusz Zientara, Paweł Rutkowski and Ludosław Stobierski

., Unuvar, C. & Munir, Z.A. (2009). Sparking plasma sintering of nanometric tungsten carbide. Int. J. Refract. Met. Hard Mater. 27(1), 130–139. DOI: 10.1016/j.ijrmhm.2008.06.004. 5. Zhu, Y., Murali, S., Cai, W., Li, X., Suk, J.W., Potts, J.R. & Ruoff, R.S. (2010). Graphene and graphene oxide: synthesis, properties, and applications. Adv. Mater. 22(35), 3906–3924. DOI: 10.3144/expresspolymlett.2011.79. 6. Ramirez, C., Figueiredo, F.M., Miranzo, P., Poza, P. & Osendi, M.I. (2012). Graphene nanoplatelet/silicon nitride composites with high electrical conductivity

Open access

D.-S. Kim, V. Dhand, K.-Y. Rhee and S.-J. Park

REFERENCES [1] A.K. Geim, K.S. Novoselov, Nat. Mater. 6 , 183 (2007). [2] K.S. Novoselov, A.K. Geim, S.V. Morozov, D. Jiang, Y. Zhang, S.V. Dubonos, I.V. Grigorieva, A.A. Firsov, Science. 306 , 666 (2004). [3] Y.B. Zhang, Y.W. Tan, H.L. Stormer, P. Kim, Nature. 438 , 201 (2005). [4] A.A. Balandin, S. Ghosh, W. Bao, I. Calizo, D. Teweldebrhan, F. Miao, C.N. Lau, Nano. Lett. 8 , 902 (2008). [5] J. Moser, A. Barrieiro, A. Bachtold, Current-induced cleaning of graphene, Appl. Phys. Lett. 91 , 163513 (2007). [6] J.R. Potts, D

Open access

K. Pietrzak, A. Gładki, K. Frydman, D. Wójcik-Grzybek, A. Strojny-Nędza and T. Wejrzanowski

). [5] J.H. Lehman, M. Terrones, E. Mansfield, Carbon 49 , 2581-2602 (2011). [6] E. Pop, A. Varshney, K. Roy, MRS Bull. 37 , 1273 (2012). [7] Scientific Background on the Nobel Prize in Physics 2010, Graphene, compiled by the Class for Physics of the Royal Swedish Academy of Sciences, 5 October 2010. [8] L. Hasselma, F. Johnson, J. Compos. Mater. 21 , 508-515 (1987). [9] K. Jagannadham, J. Vac. Sci. Technol. B 30 , 039-109 (2012). [10] F. Chen, J. Ying, Y. Wang, Carbon 96 , 836-842 (2016). [11] J. Seo, W.S. Chang, T. Kima, Thin

Open access

D. Racolta and C. Micu

, L. Zhang, S. Lee, H. Dai, Science 319 (2008) 1229. [5] L. Ci, Z. Xu, L. Wang, W. Gao, F. Ding, K.F. Kelly, B. I. Yakobson, P. M. Ajayan, Nano Res. 1 (2008) 116. [6] Z. Jiang, E. A. Henriksen, L. C. Tung, Y.-J. Wang, M. E. Schwartz, M. Y. Han, P. Kim, and H. L. Stormer, Phys. Rev. Lett. 98 (2007) 197403. [7] C. Neto et al, Phys World 105 (2006) 33. [8] Y. W. Son , M. L. Cohen M L and S. G. Louie, Phys. Rev. Lett. 97 (2006) 216803. [9] M. I. Katsnelson, 2 Graphene: Carbon in Two