http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : mmeli, Mark Hermann (검색결과 19 건)
- 무료
- 기관 내 무료
- 유료
-
Rü,mmeli, Mark H.,Rocha, Claudia G.,Ortmann, Frank,Ibrahim, Imad,Sevincli, Haldun,Bö,rrnert, Felix,Kunstmann, Jens,Bachmatiuk, Alicja,Pö,tschke, Markus,Shiraishi, Masashi,Meyyappan, M.,B&u WILEY‐VCH Verlag 2011 ADVANCED MATERIALS Vol.23 No.39
<P><B>Abstract</B></P><P>Graphene has a multitude of striking properties that make it an exceedingly attractive material for various applications, many of which will emerge over the next decade. However, one of the most promising applications lie in exploiting its peculiar electronic properties which are governed by its electrons obeying a linear dispersion relation. This leads to the observation of half integer quantum hall effect and the absence of localization. The latter is attractive for graphene‐based field effect transistors. However, if graphene is to be the material for future electronics, then significant hurdles need to be surmounted, namely, it needs to be mass produced in an economically viable manner and be of high crystalline quality with no or virtually no defects or grains boundaries. Moreover, it will need to be processable with atomic precision. Hence, the future of graphene as a material for electronic based devices will depend heavily on our ability to piece graphene together as a single crystal and define its edges with atomic precision. In this progress report, the properties of graphene that make it so attractive as a material for electronics is introduced to the reader. The focus then centers on current synthesis strategies for graphene and their weaknesses in terms of electronics applications are highlighted.</P>
-
On the Role of Vapor Trapping for Chemical Vapor Deposition (CVD) Grown Graphene over Copper
Rü,mmeli, Mark H.,Gorantla, Sandeep,Bachmatiuk, Alicja,Phieler, Johannes,Geißler, Nicole,Ibrahim, Imad,Pang, Jinbo,Eckert, Jü,rgen American Chemical Society 2013 Chemistry of materials Vol.25 No.24
<P>The role of sample chamber configuration for the chemical vapor deposition of graphene over copper was investigated in detail. A configuration in which the gas flow is unrestricted was shown to lead to graphene with an inhomogeneous number of layers (between 1 and 3). An alternative configuration in which one end of the inner tube (in which the sample is placed) is closed so as to restrict the gas flow leads a homogeneous graphene layer number. Depending on the sample placement, either homogeneous monolayer or bilayer graphene is obtained. Under our growth conditions, the data show local conditions play a role on layer homogeneity such that under quasi-static equilibrium gas conditions not only is the layer number stabilized, but the quality of the graphene improves. In short, our data suggests vapor trapping can trap Cu species leading to higher carbon concentrations, which determines layer number and improved decomposition of the carbon feedstock (CH<SUB>4</SUB>), which leads to higher quality graphene.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2013/cmatex.2013.25.issue-24/cm401669k/production/images/medium/cm-2013-01669k_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm401669k'>ACS Electronic Supporting Info</A></P>
-
Insights into the Early Growth of Homogeneous Single-Layer Graphene over Ni–Mo Binary Substrates
Rü,mmeli, Mark H.,Zeng, Mengqi,Melkhanova, Svetlana,Gorantla, Sandeep,Bachmatiuk, Alicja,Fu, Lei,Yan, Chenglin,Oswald, Steffen,Mendes, Rafael G.,Makarov, Denys,Schmidt, Oliver,Eckert, Jü,r American Chemical Society 2013 Chemistry of materials Vol.25 No.19
<P>The employment of Ni–Mo films has recently been shown to yield strictly homogeneous single-layer graphene. In this study, we systematically investigate the different stages of nucleation and growth of graphene over Ni–Mo layers. The studies reveal that the Ni film breaks up and diffuses into the underlying Mo foil, forming a Ni–Mo intermetallic. Nucleation only occurs from Ni sites, and thus, the nucleation density can be controlled by the Ni film thickness. Both nucleation and growth of the graphene are shown to be susceptible to very efficient self-termination processes to the formation of molybdenum carbide, and this guarantees the formation of large area graphene that consists <I>entirely</I> of monolayer graphene.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2013/cmatex.2013.25.issue-19/cm4020783/production/images/medium/cm-2013-020783_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm4020783'>ACS Electronic Supporting Info</A></P>
-
Wen, Xin,Chen, Xuecheng,Tian, Nana,Gong, Jiang,Liu, Jie,Rü,mmeli, Mark H.,Chu, Paul K.,Mijiwska, Ewa,Tang, Tao American Chemical Society 2014 Environmental science & technology Vol.48 No.7
<P>The catalytic carbonization of polyolefin materials to synthesize carbon nanotubes (CNTs) is a promising strategy for the processing and recycling of plastic wastes, but this approach is generally limited due to the selectivity of catalysts and the difficulties in separating the polyolefin mixture. In this study, the influence of nanosized carbon black (CB) and Ni<SUB>2</SUB>O<SUB>3</SUB> as a novel combined catalyst system on catalyzing carbonization of polypropylene (PP), polyethylene (PE), polystyrene (PS) and their blends was investigated. We showed that this combination was efficient to promote the carbonization of these polymers to produce CNTs with high yields and of good quality. Catalytic pyrolysis and model carbonization experiments indicated that the carbonization mechanism was attributed to the synergistic effect of the combined catalysts rendered by CB and Ni<SUB>2</SUB>O<SUB>3</SUB>: CB catalyzed the degradation of PP, PE, and PS to selectively produce more aromatic compounds, which were subsequently dehydrogenated and reassembled into CNTs via the catalytic action of CB together with Ni particles. Moreover, the performance of the synthesized CNTs as the electrode of supercapacitor was investigated. The supercapacitor displayed a high specific capacitance as compared to supercapacitors using commercial CNTs and CB. This difference was attributed to the relatively larger specific surface areas of our synthetic CNTs and their more oxygen-containing groups.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/esthag/2014/esthag.2014.48.issue-7/es404646e/production/images/medium/es-2013-04646e_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/es404646e'>ACS Electronic Supporting Info</A></P>
-
A Growth Mechanism for Free-Standing Vertical Graphene
Zhao, Jiong,Shaygan, Mehrdad,Eckert, Jü,rgen,Meyyappan, M.,Rü,mmeli, Mark H. American Chemical Society 2014 NANO LETTERS Vol.14 No.6
<P>We propose a detailed mechanism for the growth of vertical graphene by plasma-enhanced vapor deposition. Different steps during growth including nucleation, growth, and completion of the free-standing two-dimensional structures are characterized and analyzed by transmission electron microscopy. The nucleation of vertical graphene growth is either from the buffer layer or from the surface of carbon onions. A continuum model based on the surface diffusion and moving boundary (mass flow) is developed to describe the intermediate states of the steps and the edges of graphene. The experimentally observed convergence tendency of the steps near the top edge can be explained by this model. We also observed the closure of the top edges that can possibly stop the growth. This two-dimensional vertical growth follows a self-nucleated, step-flow mode, explained for the first time.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2014/nalefd.2014.14.issue-6/nl501039c/production/images/medium/nl-2014-01039c_0007.gif'></P>
-
Free-Standing Single-Atom-Thick Iron Membranes Suspended in Graphene Pores
Zhao, Jiong,Deng, Qingming,Bachmatiuk, Alicja,Sandeep, Gorantla,Popov, Alexey,Eckert, Jü,rgen,Rü,mmeli, Mark H. American Association for the Advancement of Scienc 2014 Science Vol.343 No.6176
<P><B>Iron in Graphene</B></P><P>Carbon or other covalently bonded materials, like boron nitride, can form two-dimensional sheets because of the strong bonding between the atoms. In contrast, metals share electrons in a three-dimensional delocalized way, and this could preclude the formation of thin stable sheets. Nevertheless, <B>Zhao <I>et al.</I></B> (p. 1228) observed pure iron membranes suspended across the pores in a graphene sheet. This phenomenon was discovered when an iron chloride solution, used to process the graphene, decomposed to form pure iron films across the pores.</P>
-
-
Size-dependent nanographene oxide as a platform for efficient carboplatin release
Makharza, Sami,Cirillo, Giuseppe,Bachmatiuk, Alicja,Vittorio, Orazio,Mendes, Rafael Gregorio,Oswald, Steffen,Hampel, Silke,Rü,mmeli, Mark H. The Royal Society of Chemistry 2013 Journal of Materials Chemistry B Vol.1 No.44
-
-
Zhao, Jiong,Deng, Qingming,Avdoshenko, Stanislav M.,Fu, Lei,Eckert, Jü,rgen,Rü,ü,mmeli, Mark H. National Academy of Sciences 2014 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.111 No.44
<P><B>Significance</B></P><P>The single metal atom has been proposed to be a catalyst during the growth of carbon nanotubes; however, this hypothesis is still not confirmed. Our direct in situ transmission EM observation of the restructuring of the graphene edges interacting with an Fe atom directly revealed the intermediate states: pentagon and hexagon structures. In particular, our experiments and simulations show that the single Fe atom behaves differently on the graphene zigzag and armchair edges, giving insights to the growth mechanisms of various sp<SUP>2</SUP> carbon structures.</P><P>Single-atom catalysts are of great interest because of their high efficiency. In the case of chemically deposited sp<SUP>2</SUP> carbon, the implementation of a single transition metal atom for growth can provide crucial insight into the formation mechanisms of graphene and carbon nanotubes. This knowledge is particularly important if we are to overcome fabrication difficulties in these materials and fully take advantage of their distinct band structures and physical properties. In this work, we present atomically resolved transmission EM in situ investigations of single Fe atoms at graphene edges. Our in situ observations show individual iron atoms diffusing along an edge either removing or adding carbon atoms (viz., catalytic action). The experimental observations of the catalytic behavior of a single Fe atom are in excellent agreement with supporting theoretical studies. In addition, the kinetics of Fe atoms at graphene edges are shown to exhibit anomalous diffusion, which again, is in agreement with our theoretical investigations.</P>
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
