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Chemical functionalization of single walled carbon nanotubes
Urszula Dettlaff-Weglikowska,Jean-Michel Benoit,Po-Wen Chiu,Ralf Graupner,Sergey Lebedkin,Siegmar Roth 한국물리학회 2002 Current Applied Physics Vol.2 No.6
Chemical modication has been performed on puried single walled carbon nanotubes. XPS spectrum shows that the peaksequent coupling reactions were carried out with diamine molecules to form intertube connections. Tripropylentetramine andphenylendiamine have been chosen as a molecular linker. End-to-side and end-to-end nanotube interconnections are formed andthen observed by atomic force microscopy (AFM). Statistical analysis made from AFM images shows around 30% junctions infunctionalized and less than 2% in pristine material. Remarkable features can be observed in the Raman spectra at dierentfunctionalization steps. Simple conductance measurements on bucky papers prepared from prestine nanotubes and from nanotubes. 2002 Elsevier Science B.V. All rights reserved.
Surface Modulation of Graphene Field Effect Transistors on Periodic Trench Structure
Jin, Jun Eon,Choi, Jun Hee,Yun, Hoyeol,Jang, Ho-Kyun,Lee, Byung Chul,Choi, Ajeong,Joo, Min-Kyu,Dettlaff-Weglikowska, Urszula,Roth, Siegmar,Lee, Sang Wook,Lee, Jae Woo,Kim, Gyu Tae American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.28
<P>In this work, graphene field effect transistors (FETs) were fabricated on a trench structure made by carbonized poly(methylmethacrylate) to modify the graphene surface. The trench-structured devices showed different characteristics depending on the channel orientation and the pitch size of the trenches as well as channel area in the FETs. Periodic corrugations and barriers of suspended graphene on the trench structure were measured by atomic force microscopy and electrostatic force microscopy. Regular barriers of 160 mV were observed for the trench structure with graphene. To confirm the transfer mechanism in the FETs depending on the channel orientation, the ratio of experimental mobility (3.6-3.74) was extracted from the current voltage characteristics using equivalent circuit simulation. It is shown that the number of barriers increases as the pitch size decreases because the number of corrugations increases from different trench pitches. The noise for the 140 nm pitch trench is 1 order of magnitude higher than that for the 200 nm pitch trench.</P>
Piao, Mingxing,Joo, Min-Kyu,Na, Junhong,Kim, Yun-Jeong,Mouis, Mireille,Ghibaudo, Gé,rard,Roth, Siegmar,Kim, Wung-Yeon,Jang, Ho-Kyun,Kennedy, Gary P.,Dettlaff-Weglikowska, Urszula,Kim, Gyu-Tae American Chemical Society 2014 The Journal of Physical Chemistry Part C Vol.118 No.46
<P>The thermoelectric power (TEP) of single walled carbon nanotube (SWCNT) thin films in pure metallic SWCNT (m-SWCNT) and pure semiconducting SWCNT (s-SWCNT) networks as well as in m- and s-SWCNT mixtures is investigated. The TEP measured on the pure s-SWCNT film (≈88 μV/K) was found to be almost 7 times higher than that of the m-SWCNTs (≈13 μV/K). Moreover, a quasilinear increase of TEP of the mixed SWCNT networks was observed as the fraction of s-SWCNTs is increased. The experimentally determined relationship between TEP and the fraction of s-SWCNTs in the mixture allows fast and simple quantitative analysis of the s:m ratio in any as-prepared heterogeneous SWCNT network. Furthermore, a semiempirical model analyzing the effect of the intertube junctions is proposed and applied to describe the thermoelectric behavior of the prepared SWCNT networks. The results of calculations match well with the experimental data and clearly demonstrate that the measured TEP of thin SWCNT films is principally controlled by the intertube junctions. The fundamental role of junctions in generating thermoelectric power is not limited to only SWCNT networks as discovered here, but also could be applied to systems where nanoparticles/nanotube form percolating paths in thin films and composite materials.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2014/jpccck.2014.118.issue-46/jp505682f/production/images/medium/jp-2014-05682f_0010.gif'></P>