ICMCTF2015 Session TS4: Graphene and 2D Nanostructures

Monday, April 20, 2015 1:30 PM in Room Royal Palm 1-3
Monday Afternoon

Time Period MoA Sessions | Abstract Timeline | Topic TS Sessions | Time Periods | Topics | ICMCTF2015 Schedule

Start Invited? Item
1:30 PM TS4-1 The Method to Growth of Porous Graphene by Chemical Vapor Deposition and the Application of NO2 Gas Sensor and the Food Additives Molecules
Kai-Chun Huang, Jyh-Ming Ting (National Cheng Kung University, Taiwan)

The use of graphene in electrochemical and gas sensors is reported. Graphene was first obtained using a chemical vapor deposition technique. In a typical process, TiO2, Pt, or Ni was deposited on copper foil substrates to produce different porous graphene deposits. The resulting graphene also has a controllable number of layers, which is critical for use in electrochemical sensor. The obtained graphene was characterized using atomic force microscopy, scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. Selected graphene was then fabricated into sensor to detect Na2S2O4. Cyclic voltammetry and differential pulse voltammetry test were carried out to examine the sensor performance. The effects of the morphology, the exposed graphene edges on the selectivity, sensitivity, and recovery properties of the sensor are addressed and discussed. The sensor performance was also correlated to these characteristics and improvement of the sensitivity was then achieved. We show that the graphene exhibits excellent response to NO2 gas and a food additive molecule of Na2S2O4 at room temperature.

1:50 PM TS4-2 Nucleation and Growth of Sputtered Two-Dimensional Transition Metal Dichacogenides
Christopher Muratore (University of Dayton, USA); Michael Jespersen, John Bultman, Jianjun Hu (University of Dayton Research Institute; Air Force Research Laboratory, USA); Rachel Naguy (Air Force Research Laboratory; University of Dayton, USA); Michael McConney, Nicholas Glavin, Randy Stevenson (Air Force Research Laboratory, USA); Adam Waite (UTC/Air Force Research Laboratory; University of Dayton, USA); Md.Aman Haque (Penn State University, USA); Arthur Safriet (University of Dayton Research Institute; Air Force Research Laboratory, USA); Michael Check, Andrey Voevodin (Air Force Research Laboratory, USA)

Physical vapor deposition (PVD) is an expensive and complicated way to process materials, however, the exquisite control of structure and composition and freedom from many thermodynamic constraints make it worthwhile. This is evidenced by the common use of sputter deposition in a significant fraction of the total fabrication steps required to produce ubiquitous commercial electronic devices. By employing well-known theories of film growth and making the necessary conditions a reality through the use of surface engineering technology, thin film microstructures become very tailorable via PVD. This is of particular importance in the field of two dimensional (2D) materials, where processing of continuous and uniform films with thicknesses on the order of 1 nm is currently a major challenge. Transition metal dichalcogenides (TMDs), such as MoS2 are currently under extensive study as high-performance 2D semiconductors. Using PVD techniques, which are easy to integrate into existing semiconductor device fabrication processes, 2D TMDs can be grown on diverse substrates including SiO2, graphene, metals, and polymers. This is surprising as it is more common for such thin films to form isolated islands on substrates. Using a variety of in situ and conventional ex situ materials characterization tools such as Raman spectroscopy and X-ray photoelectron spectroscopy, the mechanisms governing continuous growth of TMDs have been examined for all of the substrates listed above. These substrates possess a broad range of surface energies. It appears that under some conditions a continuous metal monolayer is formed initially on higher surface energy substrates, and normal TMD growth continues on that interfacial metal layer. This is typically observed at high temperature where preferential desorption of the chalcogen atoms during growth is enhanced. Initial studies also suggest that growth mechanisms for Mo-based (MoS2 and MoSe2) TMDs are different than that which occurs for analogous W-based compounds (WS2 and WSe2). A comprehensive model allowing prediction of other TMD microstructures is put forward based on the experimental studies. This fundamental understanding will be used to show how the crystalline domain size within 1-5 nm thick TMD films can be manipulated during PVD growth over at least one order of magnitude.

2:10 PM Invited TS4-3 Phonon Transport in Graphene: Graphene Applications in Thermal Coatings
Alexander Balandin (University of California – Riverside, USA)

Unique electronic properties of graphene originate from its unusual linear Dirac-cone dispersion. Phonons – quanta of lattice vibrations – in two-dimensional crystals also reveal features different from those in bulk materials. We discovered that the phonon thermal conductivity of suspended graphene can be exceptionally high – above ~2000 W/mK at room temperature – exceeding that of the basal graphite planes [1]. We explained this fact by quenching of the phonon scattering processes in two-dimensional systems and resulting anomalously long mean free path of the low-frequency acoustic phonons in graphene [2-3]. In this talk, I will review results of our studies of thermal properties of graphene and describe practical applications of graphene-based materials as thermal coatings for heat removal from advanced electronics. Specific examples of thermal coating applications will include graphene and few-layer graphene heat spreaders for high-power-density GaN electronics [4], graphene-enhanced thermal interface materials [5], graphene – copper heterostructures and prototype interconnects [6] and graphene laminate coatings on flexible substrates [7]. Our results suggest that thermal coatings and thermal management materials can become the first major commercial applications of graphene.

[1] A.A. Balandin, et al., Nano Lett., 8, 902 (2008); [2] S. Ghosh, et al., Nature Mat., 9, 555 (2010); [3] A.A. Balandin, Nature Mat., 10, 569 (2011); [4] Z. Yan, et al., Nature Comm., 3, 827 (2012); [5] K.F. Shahil and A.A. Balandin, Nano Lett., 12, 861 (2012); [6] P. Goli, H. Ning, K.S. Novoselov and A.A. Balandin, Nano Lett., 14, 1497 (2014); H. Malekpour, K.-H. Chang, D. L. Nika, K. S. Novoselov and A. A. Balandin, Nano Lett., 14, 5155 (2014).

2:50 PM TS4-5 Orientation-Dependent Binding Energy of Graphene on the Pd(111) Surface
Branden Kappes (Colorado School of Mines, USA); Abbas Ebnonnasir, Suneel Kodambaka (UCLA, USA); Cristian Ciobanu (Colorado School of Mines, USA)
Using density functional theory calculations, we show that the binding strength of a graphene monolayer on Pd(111) can vary between physisorption and chemisorption depending on its orientation. By studying the interfacial charge transfer, we have identified a specific four-atom carbon cluster that is responsible for the local bonding of graphene to Pd(111). The areal density of such clusters varies with the in-plane orientation of graphene, causing the binding energy to change accordingly. Similar investigations can also apply to other metal substrates and suggests that physical, chemical, and mechanical properties of graphene may be controlled by changing its orientation. These results have recently been published in Applied Physics Letters.
3:10 PM TS4-6 Characterization and Potential Gas Sorption Applications of Nanoporous Spongy Graphene Synthesized by Wet Chemical Reduction and Freeze Drying
Nikolaos Kostoglou (University of Cyprus, Cyprus); Georgios Constantinides (Cyprus University of Technology, Cyprus); Georgia Charalambopoulou, Theodore Steriotis (National Center for Scientific Research Demokritos, Greece); Yuanqing Li, Kin Liao, Kyriaki Polychronopoulou (Khalifa University of Science, Technology & Research, UAE); Vladislav Ryzhkov (Fibrtec Incorporation, USA); Christian Mitterer (Montanuniversität Leoben, Austria); Claus Rebholz (University of Cyprus, Cyprus)

Chemically or micro-mechanically exfoliated 2D graphene has been a subject of considerable research during the last decade due to its unique electrical, thermal and mechanical properties. Porous graphene-based nanostructures combine multiple advantages such as lightweight, large surface areas and pore volumes, as well as thermal and chemical stability. Therefore, these nanostructures have the potential to be used in a series of applications including gas storage/separation, water purification and as catalyst substrates. In the present work, a nanoporous (average pore width ~0.7 nm) graphene sponge-like structure with large-specific surface area (~350 m2/g) and high-oxygen content (~15 at.%) was synthesized by wet chemical reduction of graphene oxide in combination with freeze-drying. The surface morphology and elemental composition of the spongy graphene were studied by Scanning Electron Microscopy combined with Energy Dispersive X-ray Spectroscopy, while the respective structure was investigated by X-ray Diffraction analysis. Textural properties, including specific surface area (determined by the Brunauer-Emmet-Teller method), micropore volume and surface area (determined by the Carbon Black statistical thickness method), as well as pore size distribution (determined by the Quenched Solid Density Functional Theory method) were deduced from nitrogen gas adsorption/desorption data obtained at 77 K and pressures up to 1 bar. The obtained characterization results were used as a basis for the comparison of the spongy graphene with commercially available graphene nanoplatelets of high-crystallinity. In addition their potential for gas sorption applications was preliminary assessed by low-pressure carbon dioxide, methane and hydrogen sorption measurements.

3:30 PM TS4-7 Graphene Content-Sliding Speed Relation in the Ni-Graphene Nanocomposites Produced by Pulse Electrodeposition
Hasan Algul, Mahmud Tokur, Seyma Ozcan, Mehmet Uysal, Ahmet Alp, Hatem Akbulut (Sakarya University, Turkey)

Ni matrix reinforced with ceramic particles and fibers have been widely used in automobile and aerospace industries because of their excellent mechanical properties, wear resistance and corrosion resistance [1]. Graphene incorporated into the Ni matrix are expected to exhibit even higher hardness and strength, since the wear mechanism of graphene is proposed to be due to breakage of in-plane bonds between carbon atoms and shearing at the interface of graphene layers [2]

Nickel/graphene metal matrix composite coatings were deposited by pulse electro co-deposition method from a Watt's type electrolyte. The influence of the graphene concentration in the electrolyte on the particle co-deposition and distribution, the surface morphology, microstructure, microhardness, tribological features of nanocomposite coatings were studied. Microhardness of the composite coating was measured using a Vicker's microhardness indenter. SEM, EDS and XRD analysis were used to determine chemical composition and structure of composite coatings. The tribological behaviors of the electrodeposited nano composite coatings sliding against ceramic balls were examined on a CSM Instrument. The tribological behavior of the resultant composite coating was tested by a reciprocating ball-on disk method at constant load but varying sliding speeds for determination the wear loss and friction coefficient features against a counterface. All the friction and wear tests were performed without lubrication at room temperature and in the ambient air (with a relative humidity of 55–65 %). The change in wear mechanisms by changing graphene nanosheets content was also comprehensively studied. Special attention was given to the effect of sliding speed, graphene nanosheet content on the tribological performance of the nanocomposites.


[1] J. Xu, J. Tao, S. Jiang, Z. Xu, Applied Surface Science, 254 (2008), pp. 4036–4043

[2] W. Zhai, X. Shi, M. Wang, Z. Xu, J. Yao, S. Song, Y. Wang, Wear, 310 (2014) 33–40

3:50 PM TS4-8 Graphene as a Protective Coating and Superior Lubricant for Electrical Contacts
Diana Berman, Ali Erdemir, Anirudha Sumant (Argonne National Laboratory, USA)

Providing reliable coatings for rotating/sliding electrical contacts, suffering from mechanical wear is extremely important in various applications. Apart from graphene’s unique ability to drastically reduce friction and wear in mechanical systems, we have investigated its potential to serve as an excellent electrical conductor in sliding contacts. We have looked at gold surface rubbing against titanium nitride coated steel ball in an pin-on-disc macroscale tribometer while monitoring the electrical resistance of the gold/titanium nitride contact during the test. We have observed that in presence of few layer graphene, even under high contact pressures (up to 0.5 GPa contact pressure), both friction and wear significantly reduces by as much as 2-3 times and 2 orders of magnitude respectively both in humid and in dry environments. More importantly, the contact resistance stays low and stable (within 5% deviation) for longer period (4000 cycles). These results open a new niche for graphene films to be used as flexible, transparent, and wear resistant conducting electrodes where the atomically thin nature of graphene coupled with superior mechanical and electrical performance makes graphene very unique and fitting.


Use of the Center for Nanoscale Materials was supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

4:10 PM TS4-9 Three-Dimensional Textured Graphene Bioelectronics
MichaelCai Wang, Jonghyun Choi, Ali Ashraf, KeongHan Yong, Juyoung Leem, SungWoo Nam (University of Illinois at Urbana-Champaign, USA)
Superb electromechanical properties of graphene, where large elastic deformation is achievable without significant perturbation of electrical properties, provide a substantial promise for flexible electronics, advanced nanoelectromechanical and bioelectronic devices. We report three-dimensional (3D) field-effect transistor biosensors built from the monolithic integration of crumpled graphene and graphite. First, we present monolithic synthesis of graphene-graphite for all-carbon bioelectronic transistor arrays. Second, we develop a rapid and scalable method of texturing 2-dimensional (2D) graphene by using soft-matter transformation of shape-memory polymers into 3D bioelectronic sensors. We demonstrate that the thermally-induced transformation of graphene on a polymeric substrate creates 3D textured graphene. Quantitative analysis shows that both the wavelength and height of textured graphene are a few micrometers at an applied strain of 70% and that the 3-dimensionality of graphene (i.e., wavelength and height of texturing) can be controlled by the processing parameters. We further characterize the electrical and mechanical properties of 3D graphene, and demonstrate the robust electromechanical properties of 3D textured graphene. Finally, we explore biosensor device applications by constructing an array of field-effect biosensors. We believe our approach to forming textured graphene by soft-matter transformation offers a unique avenue for creating advanced and 3D bioelectronic devices, and furthermore, these unique capabilities could be exploited in chemical and biological detection and conformal interface with biological systems in the future.
4:30 PM Invited TS4-10 Layer-by-Layer Thin Film Based on Reduced Graphene Oxide: A Surface Coating That Can Be Antiseptized within Minutes of Solar Exposure
Liwei Hui, Jeffrey T. Auletta, Zhiyu Huang, Xiang Chen, Fei Xia, Shengfeng Yang, Haitao Liu, Lihua Yang (University of Science and Technology of China, China)

Graphene oxide (GO) was reported to be bactericidal in saline whereas its activity in nutrient broth was controversial. By performing antibacterial assays under comparable conditions, we show that bare GO intrinsically kills both bacteria and mammalian cells but the non-covalent adsorption by biomolecules commonly found in biologically relevant environments on GO basal planes readily deactivates its activity. Similarly, graphene and reduced graphene oxide (rGO) have demonstrated bactericidal activity to varying extent and also readily adsorb a variety of substances onto their basal planes via non-covalent adsorption. Such a dilemma makes the use of graphene and graphene-derivitized forms for practical pathogen control a challenge. To address this, we exploit the photochemical/photothermal properties of rGO. Using a layer-by-layer thin film based on rGO, >90% airborne bacteria, including antibiotic-tolerant persisters, on contact were killed within 10 min upon solar irradiation. Further experiments suggest that solar light in the near-infrared region may play dominant roles in the observed activity. This work suggests that rGO’s photothermal/photodynamic property confers rGO-based surface coating with effective antibacterial activity upon minutes of solar irradiation and sun may be alternative to a laser for potent photothermal/photodynamic cytotoxicity at ultralow irradiance.

Time Period MoA Sessions | Abstract Timeline | Topic TS Sessions | Time Periods | Topics | ICMCTF2015 Schedule