JVB Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

May 2012

Volume 30, Issue 3, Articles (03xxxx)

Issue Cover Spotlight Figure

J. Vac. Sci. Technol. B 30, 03D111 (2012); http://dx.doi.org/10.1116/1.3699011 (5 pages)

Yusuke Yamashiro, Yasuhide Ohno, Kenzo Maehashi, Koichi Inoue, and Kazuhiko Matsumoto
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Conformally coating vertically aligned carbon nanotube arrays using thermal decomposition of iron pentacarbonyl

Owen Hildreth, Baratunde Cola, Samuel Graham, and C. P. Wong

J. Vac. Sci. Technol. B 30, 03D101 (2012); http://dx.doi.org/10.1116/1.3692724 (4 pages)

Online Publication Date: 7 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Conformally coating vertically aligned carbon nanotubes (v-CNT) with metals or oxides can be difficult because standard line-of-sight deposition methods, such as dc sputter coating and electron-beam evaporation, are hindered by the low mean-free-path within the vertically aligned array. In this work, we present a facile method to conformally coat dense arrays of v-CNTs using thermal decomposition of iron pentacarbonyl at 205 °C and 30 mTorr. The resulting coatings were found to be uniform from top-to-bottom across an entire 1 × 1 cm2 array of v-CNTs. The thickness of the deposited coating was found to be 2–3 nm/cycle and the resulting film thickness were found to be 13 ± 3 nm after five cycles and 55 ± 5 nm after 20 cycles. This process demonstrates that metal organic chemical vapor deposition can be used to fabricate conformal coatings on v-CNTs.
Show PACS
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.15.Kk Vapor phase epitaxy; growth from vapor phase
68.55.jd Thickness

Photoelectron spectroscopy studies of plasma-fluorinated epitaxial graphene

Sonam D. Sherpa, Sergio A. Paniagua, Galit Levitin, Seth R. Marder, M. D. Williams, and Dennis W. Hess

J. Vac. Sci. Technol. B 30, 03D102 (2012); http://dx.doi.org/10.1116/1.3688760 (7 pages) | Cited 2 times

Online Publication Date: 7 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Fluorination of graphene has emerged as an attractive approach toward manipulating its physical, chemical, and electronic properties. To this end, we have demonstrated the viability of sulfur hexafluoride plasmas to fluorinate graphene as a safer alternative to the commonly reported techniques of fluorination that include exposures to fluorine and xenon difluoride gas. Incorporation of fluorine moieties on graphene after SF6 plasma-treatment was confirmed by x-ray photoelectron spectroscopy. Modifications in the valence band states of graphene after plasma-treatment were characterized by ultraviolet photoelectron spectroscopy. Increase in work function of plasma-treated graphene demonstrates the ability of plasma-assisted fluorination to modify the electron emission characteristics of graphene. Raman spectroscopy reveals that the majority of carbon atoms in graphene retain their sp2 hybridization after the plasma-treatment.
Show PACS
79.60.Bm Clean metal, semiconductor, and insulator surfaces
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
78.67.Wj Optical properties of graphene
71.20.Tx Fullerenes and related materials; intercalation compounds
73.20.At Surface states, band structure, electron density of states
78.30.Na Fullerenes and related materials

Effect of functionalization on the electrostatic charging, tunneling, and Raman spectroscopy of epitaxial graphene

Jeongmin Hong, Sandip Niyogi, Elena Bekyarova, Mikhail E. Itkis, Palanisamy Ramesh, Claire Berger, Walt A. deHeer, Robert C. Haddon, and Sakhrat Khizroev

J. Vac. Sci. Technol. B 30, 03D103 (2012); http://dx.doi.org/10.1116/1.3693417 (5 pages)

Online Publication Date: 12 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report the effects of radical functionalization on the electrostatic force microscopy (EFM), the scanning tunneling spectra (STS), and Raman spectroscopy of epitaxial graphene. The EFM studies show the existence of layer-dependent trapped charges in the pristine graphene. The uniform enhancement of energy gap is observed through STS. Raman spectra show nonuniformly distributed D-band intensities throughout the functionalized sample as a result of the inhomogeneous distribution of covalent bonds to the graphene sheets. The functionalization chemistry has a marked effect on the homogeneity of the electrostatic charge and leads to an increase of the energy of the band gap.
Show PACS
73.22.Pr Electronic structure of graphene
78.67.Wj Optical properties of graphene
81.05.ue Graphene
78.30.Na Fullerenes and related materials
61.48.Gh Structure of graphene
72.80.Vp Electronic transport in graphene

Fabrication of top-gated epitaxial graphene nanoribbon FETs using hydrogen-silsesquioxane

Wan Sik Hwang, Kristof Tahy, Luke O. Nyakiti, Virginia D. Wheeler, Rachael. L. Myers-Ward, C. R. Eddy, Jr., D. Kurt Gaskill, Huili (Grace) Xing, Alan Seabaugh, and Debdeep Jena

J. Vac. Sci. Technol. B 30, 03D104 (2012); http://dx.doi.org/10.1116/1.3693593 (4 pages) | Cited 3 times

Online Publication Date: 12 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Top-gated epitaxial graphene nanoribbon (EGNR) field effect transistors (FETs) were fabricated on epitaxial graphene substrates which demonstrated the opening of a substantial bandgap. Hydrogen silsesquioxane (HSQ) was used for the patterning of 10 nm size linewidth as well as a seed layer for atomic layer deposition (ALD) of a high-k dielectric aluminum oxide (Al2O3). It is found that the resolution of the patterning is affected by the development temperature, electron beam dose, and substrate materials. The chosen gate stack of HSQ followed by Al2O3 ALD permits stable device performance and enables the demonstration of the EGNR-FET.
Show PACS
85.30.Tv Field effect devices

Enormous shrinkage of carbon nanotubes by supersonic stress and low-acceleration electron beam irradiation

Jun-ichi Fujita, Teppei Takahashi, Ryuichi Ueki, Takeshi Hikata, Soichiro Okubo, Risa Utsunomiya, and Teruaki Matsuba

J. Vac. Sci. Technol. B 30, 03D105 (2012); http://dx.doi.org/10.1116/1.3694027 (5 pages)

Online Publication Date: 15 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors demonstrated a new method for inducing enormous shrinkage in single-walled carbon nanotube bundles by applying low energy electron beam irradiation along with supersonic vibration, and a maximum shrinkage rate of −100% cm2/C was obtained under electron acceleration of 1 keV. The characteristic feature of the shrunken single-walled carbon nanotubes was a wavy deformation that affected the entire bundle. The authors believe that a uniaxial stress induced by the supersonic vibration broke the equilibrium of the internal stress and allowed the uniform accumulation of defects under low energy electron beam excitation. The wavy deformation of the single-walled carbon nanotubes resulted in the enormous shrinkage of the bundle.
Show PACS
81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity
61.82.-d Radiation effects on specific materials
61.72.-y Defects and impurities in crystals; microstructure
61.48.De Structure of carbon nanotubes, boron nanotubes, and other related systems

Graphene stripper foils

Igor Pavlovsky and Richard L. Fink

J. Vac. Sci. Technol. B 30, 03D106 (2012); http://dx.doi.org/10.1116/1.3693594 (5 pages)

Online Publication Date: 20 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Thin carbon and metal foils have been used in heavy ion accelerators for charge stripping. The power dissipated by a particle beam in a foil can be as high as 3 kW or greater, which results in short lifetimes of conventional stripper foils. Graphene stripper foils can overcome critical limitations of other materials due to a unique combination of their exceptional physical properties. The authors have fabricated graphene foils with diameters up to 13 cm and area densities of 0.1 to 3.0 mg/cm2 by reduction of graphene oxide in an aqueous dispersion followed by pressure filtration. The foils were characterized by a number of analytical techniques, including scanning electron microscopy, thermogravimetric analysis, and x-ray photoelectron spectroscopy, and proved their superior mechanical and thermal properties. Preliminary ion beam tests showed that the graphene stripper foils possess up to four times longer lifetime, as opposed to conventional carbon foils.
Show PACS
81.05.ue Graphene
65.80.Ck Thermal properties of graphene
61.48.Gh Structure of graphene
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity

Surface functionalization of graphenelike materials by carbon monoxide atmospheric plasma treatment for improved wetting without structural degradation

Rafael J. Zaldivar, Paul M. Adams, Jim Nokes, and Hyun I. Kim

J. Vac. Sci. Technol. B 30, 03D107 (2012); http://dx.doi.org/10.1116/1.3695337 (7 pages)

Online Publication Date: 22 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Oxygen plasma treatment has been extensively used to functionalize the surface of graphenelike materials. However, functionalization is usually accompanied by degradation of the structure, which may affect mechanical and electrical performance. Atmospheric plasma treatment (APT) of HOPG was performed to compare the effect of surface modification using carbon monoxide (CO) as the active gas, in comparison to O2. Both Raman and STM demonstrated nanoscale degradation of the structure when using the O2 treatment. CO treated specimens exhibited no observable damage to the material with high levels of oxygen incorporation. Instead, a well ordered monolayer of oxygen-containing film was observed on the surface of the specimens which could accommodate high levels of surface oxygen. Changes in surface characteristics were analyzed using x-ray photoelectron spectroscopy (XPS) as a function of duration. The results indicated that the use of O2 plasma resulted in only a limited oxygen uptake (O/C = 0.11), while CO APT resulted in tailorable surface O/C ratios as high as 0.65, a result not observed even when using low-pressure radio frequency plasmas. XPS analysis and Auger spectroscopy confirmed that a tailorable level of carbonyl functional groups could be evenly distributed throughout the surface. Contact angle measurements verified the formation of a highly stable hydrophilic surface. The CO treatment was also successfully applied to other nanocarbon materials such as graphene nanoplatelets with similar results.
Show PACS
81.65.-b Surface treatments
78.67.Wj Optical properties of graphene
79.60.Bm Clean metal, semiconductor, and insulator surfaces
78.30.Na Fullerenes and related materials
61.48.Gh Structure of graphene

Complementary voltage inverters with large noise margin based on carbon nanotube field-effect transistors with SiNx top-gate insulators

Kenzo Maehashi, Takaomi Kishimoto, Yasuhide Ohno, Koichi Inoue, and Kazuhiko Matsumoto

J. Vac. Sci. Technol. B 30, 03D108 (2012); http://dx.doi.org/10.1116/1.3697527 (4 pages)

Online Publication Date: 23 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Complementary voltage inverters based on top-gated carbon nanotube field-effect transistors (CNTFETs) were fabricated with SiNx top-gate insulators. The SiNx passivation films were deposited by catalytic chemical vapor deposition, and the carrier type of the CNTFETs was controlled by the conditions used to form the passivation film. Air-stable complementary voltage inverters incorporating p- and n-type CNTFETs were then fabricated on the same SiO2 substrate. The static transfer and noise margin characteristics of the CNTFET-based inverters were investigated. A high gain of 24 at an input voltage of 0.49 V and a large noise margin equal to 80% of half the supply voltage were achieved. This approach is a useful technique for fabricating integrated logic devices and circuits based on CNTFETs.
Show PACS
85.30.Tv Field effect devices
85.35.Kt Nanotube devices
85.40.Sz Deposition technology
84.30.Sk Pulse and digital circuits

Electrical conductivity of copper–graphene composite films synthesized by electrochemical deposition with exfoliated graphene platelets

Kasichainula Jagannadham

J. Vac. Sci. Technol. B 30, 03D109 (2012); http://dx.doi.org/10.1116/1.3701701 (9 pages)

Online Publication Date: 16 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Films of graphene/copper composite in copper matrix were deposited on copper foil using an aqueous electrolyte solution of 0.2 M CuSO4 containing graphene oxide suspension at a low current density of 1.75 mA cm−2. Graphene oxide is reduced by further heating the samples in flowing hydrogen atmosphere maintained at 20 Torr and 400 °C for 3 h. The composite samples with different thickness, between 365 and 515 μm, deposited on a Cu foil of thickness 135 μm were characterized for graphene structure, morphology, and distribution. Electrical resistivity and temperature coefficient of electrical resistance of the samples at 300 K were measured using a four-probe method. The results were used to determine the electrical resistivity and temperature coefficient of resistance of the composite layers. The volume fraction and resistivity of graphene were evaluated using effective mean field analysis of the resistivity and temperature coefficient of resistance of the composite films. The results illustrate that the resistivity of graphene is much lower than that of copper and copper–graphene composite films are favorable for electrofriction applications.
Show PACS
81.05.ue Graphene
73.61.Wp Fullerenes and related materials
81.15.Pq Electrodeposition, electroplating

Bilayer graphene by bonding CVD graphene to epitaxial graphene

Glenn G. Jernigan, Travis J. Anderson, Jeremy T. Robinson, Joshua D. Caldwell, Jim C. Culbertson, Rachael Myers-Ward, Anthony L. Davidson, Mario G. Ancona, Virginia D. Wheeler, Luke O. Nyakiti, Adam L. Friedman, Paul M. Campbell, and D. Kurt Gaskill

J. Vac. Sci. Technol. B 30, 03D110 (2012); http://dx.doi.org/10.1116/1.3701700 (5 pages) | Cited 1 time

Online Publication Date: 17 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A novel method for creating bilayer graphene is described where single-layer CVD graphene grown on Cu is bonded to single-layer epitaxial graphene grown on Si-face SiC. Raman microscopy and x ray photoelectron spectroscopy demonstrate the uniqueness of this bilayer, as compared to a naturally formed bilayer, in that a Bernal stack is not formed with each layer being strained differently yet being closely coupled. Electrical characterization of Hall devices fabricated on the unusual bilayer show higher mobilities, and lower carrier concentrations, than the individual CVD graphene or epitaxial graphene layers.
Show PACS
68.65.Pq Graphene films
72.80.Vp Electronic transport in graphene
78.67.Wj Optical properties of graphene
72.20.My Galvanomagnetic and other magnetotransport effects
78.30.Na Fullerenes and related materials
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)

Electric-field-induced band gap of bilayer graphene in ionic liquid

Yusuke Yamashiro, Yasuhide Ohno, Kenzo Maehashi, Koichi Inoue, and Kazuhiko Matsumoto

J. Vac. Sci. Technol. B 30, 03D111 (2012); http://dx.doi.org/10.1116/1.3699011 (5 pages) | Cited 1 time

Online Publication Date: 18 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ionic liquid-gated graphene field-effect-transistors (G-FETs) were fabricated to generate a band gap in bilayer graphene. The transfer characteristics of the G-FETs revealed that the transconductance when using the ionic-liquid gate was significantly higher than that when using the back gate, because an electrical double layer formed in the ionic liquid with 200-fold the capacitance of a 300-nm-thick SiO2 layer. The results indicate that the ionic-liquid-gate structure enables application of an effective electric field. Moreover, an increase in the resistance of the bilayer graphene was clearly observed as the magnitude of the electric-field intensity was increased, owing to the creation of the band gap. From measurements of electrical characteristics as a function of temperature, a band gap of 235 meV was created in bilayer graphene at an ionic-liquid-gate voltage of −3.0 V.
Show PACS
85.30.Tv Field effect devices

Valley and spin polarization from graphene line defect scattering

Daniel Gunlycke and Carter T. White

J. Vac. Sci. Technol. B 30, 03D112 (2012); http://dx.doi.org/10.1116/1.4706892 (5 pages) | Cited 3 times

Online Publication Date: 25 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Quantum transport calculations describing electron scattering off an extended line defect in graphene are presented. The calculations include potentials from local magnetic moments recently predicted to exist on sites adjacent to the line defect. The transmission probability is derived and expressed as a function of valley, spin, and angle of incidence of an electron at the Fermi level being scattered. It is shown that the previously predicted valley polarization in a beam of transmitted electrons is not significantly influenced by the presence of the magnetic moments. These moments, however, do introduce some spin polarization, in addition to the valley polarization, albeit no more than about 20%.
Show PACS
73.22.Pr Electronic structure of graphene
72.25.-b Spin polarized transport
73.20.At Surface states, band structure, electron density of states
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
75.30.Cr Saturation moments and magnetic susceptibilities

Synthesis of patterned nanographene on insulators from focused ion beam induced deposition of carbon

Gemma Rius, Masamichi Yoshimura, and Narcis Mestres

J. Vac. Sci. Technol. B 30, 03D113 (2012); http://dx.doi.org/10.1116/1.4709419 (4 pages)

Online Publication Date: 27 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A unique approach was used to synthesize nanographene directly on insulating substrates with precise positioning control. The process is comprised of two steps: (i) deposition of carbon using focused ion beam induced deposition and (ii) annealing in vacuum at mid-high temperatures using metal foil as the catalyst material. The characteristics of the carbon nanomaterial can be specified in terms of morphology, shape, thickness, and crystalline size. Ion beam induced deposition allows the definition of 3D features with submicron resolution and pattern flexibility. Metal-assisted annealing transforms the as-deposited amorphous C into nanographene, as confirmed by Raman spectroscopy.
Show PACS
81.05.ue Graphene
61.48.Gh Structure of graphene
61.46.-w Structure of nanoscale materials
81.40.Gh Other heat and thermomechanical treatments
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization

Transfer-free fabrication of graphene transistors

Pia Juliane Wessely, Frank Wessely, Emrah Birinci, Udo Schwalke, and Bernadette Riedinger

J. Vac. Sci. Technol. B 30, 03D114 (2012); http://dx.doi.org/10.1116/1.4711128 (5 pages) | Cited 1 time

Online Publication Date: 4 May 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors invented a method to fabricate graphene transistors on oxidized silicon wafers without the need to transfer graphene layers. To stimulate the growth of graphene layers on oxidized silicon, a catalyst system of nanometer thin aluminum/nickel double layer is used. This catalyst system is structured via liftoff before the wafer enters the catalytic chemical vapor deposition (CCVD) chamber. In the subsequent methane-based growth process, monolayer graphene field-effect transistors and bilayer graphene field-effect transistors are realized directly on oxidized silicon substrate, whereby the number of stacked graphene layers is determined by the selected CCVD process parameters, e.g., temperature and gas mixture. Subsequently, Raman spectroscopy is performed within the channel region in between the catalytic areas and the Raman spectra of five-layer, bilayer, and monolayer graphene confirm the existence of graphene grown by this silicon-compatible, transfer-free and in situ fabrication approach. These graphene FETs will allow a simple and low-cost integration of graphene devices for nanoelectronic applications in a hybrid silicon CMOS environment.
Show PACS
85.30.Tv Field effect devices

Temperature dependent spin precession measurements in trilayer graphene utilizing co/graphene contacts

Joseph Abel, Akitomo Matsubayashi, John J. Garramone, and Vincent P. LaBella

J. Vac. Sci. Technol. B 30, 03D115 (2012); http://dx.doi.org/10.1116/1.4709768 (4 pages) | Cited 1 time

Online Publication Date: 7 May 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The temperature dependence of the spin lifetime and spin diffusion coefficient of exfoliated multilayer graphene is measured using nonlocal spin detection and spin precession measurements. Low impedance cobalt contacts are utilized for spin injection and readout. A decrease in spin lifetime with increasing temperature is observed as well as an increase in the spin diffusion coefficient with increasing temperature. This observation provides some insight into the relevant spin relaxation mechanisms that are occurring in this trilayer graphene sample.
Show PACS
72.25.-b Spin polarized transport

Direct measurement of quasiparticle lifetimes in graphene using time-resolved photoemission

Steve Gilbertson, Tomasz Durakiewicz, Jian-Xin Zhu, Aditya D. Mohite, Andrew Dattelbaum, and George Rodriguez

J. Vac. Sci. Technol. B 30, 03D116 (2012); http://dx.doi.org/10.1116/1.4715440 (6 pages)

Online Publication Date: 15 May 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Graphene has attracted much interest for its potential applications due to its unique band structure. Although much work with graphene has recently been conducted in the time domain, questions about how the electronic properties of graphene behave in the vicinity of the linearly dispersive region remain. In this experiment, the authors use the technique of time-resolved photoemission to directly measure quasiparticle lifetimes. The results are in qualitative agreement with the predictions of a tight-binding model where lifetime is evaluated from the imaginary part of the electron self-energy. The results indicate that the excited carriers decay faster at higher excitation energies—an effect the authors attribute to increasing phase space for electron–electron and electron–phonon interactions for energies away from the Dirac point.
Show PACS
79.60.-i Photoemission and photoelectron spectra
63.20.kd Phonon-electron interactions
63.22.Rc Phonons in graphene
71.20.Tx Fullerenes and related materials; intercalation compounds
71.38.-k Polarons and electron-phonon interactions

Experimental and theoretical investigation of graphene layers on SiC(000math) in different stacking arrangements

Jakub Soltys, Jolanta Borysiuk, Jacek Piechota, and Stanislaw Krukowski

J. Vac. Sci. Technol. B 30, 03D117 (2012); http://dx.doi.org/10.1116/1.4715549 (6 pages)

Online Publication Date: 15 May 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
High-resolution transmission electron microscopy was used to investigate graphene layers formed on the C-terminated 4H-SiC(000math) surface in different arrangements, including various stacking sequences and spatial layer separation. Various stacking types such as ABAB and ABCA configurations were identified. The density functional theory (DFT) calculations of the graphene in various configurations were performed showing the following dispersion relations: AAAA—linear, ABBBA—close to linear, and ABAB—hyperbolic (strongly nonlinear). An increase of the interlayer separation of ABAB and ABCA systems leads to gradually increased linear dispersion, typical for AAAA stacking. It is shown, however, that for this transition to occur, a separation of the adjacent layers by about 5 Å is necessary, which is not likely to occur in the graphene layer grown on the SiC(000math) surface. DFT calculations employing rotation of the adjacent AB planes of bilayer graphene by either 27.7 or 32.2 arc deg demonstrate similar linear dependence, typical for single layer or double AA stacked graphene. It was therefore confirmed that the experimentally observed linear dispersion and the math dependence of the Landau levels may be explained by various stacking of carbon layers in multilayer graphene.
Show PACS
71.20.Tx Fullerenes and related materials; intercalation compounds
71.45.-d Collective effects
71.70.Di Landau levels
82.70.-y Disperse systems; complex fluids
71.15.Mb Density functional theory, local density approximation, gradient and other corrections

Graphene metal oxide composite supercapacitor electrodes

John R. Lake, Arthur Cheng, Steve Selverston, Zuki Tanaka, Jessica Koehne, M. Meyyappan, and Bin Chen

J. Vac. Sci. Technol. B 30, 03D118 (2012); http://dx.doi.org/10.1116/1.4712537 (6 pages) | Cited 2 times

Online Publication Date: 18 May 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This study presents composite electrode materials based on graphene oxide (GO) and transition metal oxide nanostructures for supercapacitor applications. Electrophoretic deposition of GO on a conductive substrate was used to form reduced graphene oxide (rGO) films through chemical reduction. The specific capacitance of the rGO was calculated up to 117 F/g at 100 mV/s scan rate from KOH (1 M) electrolyte using an Ag/AgCl reference electrode. The strong interaction of GO with Co3O4 and MnO2 nanostructures was demonstrated in the self-assembled Langmuir–Blodgett monolayer composite, showing the potential to fabricate thin film supercapacitor electrodes without using binder materials. This two-step process is nontoxic and scalable and holds promise for improved energy density from redox capacitance in comparison with the conventional double layer supercapacitors.
Show PACS
84.32.Tt Capacitors

Surface modification of gold–carbon nanotube nanohybrids under the influence of near-infrared laser exposure

Amanda M. Schrand, Bradley M. Stacy, Saber M. Hussain, Maomian Fan, Jared Speltz, Sarah Payne, and Larry Dosser

J. Vac. Sci. Technol. B 30, 03D119 (2012); http://dx.doi.org/10.1116/1.4715698 (6 pages)

Online Publication Date: 21 May 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The development of multifunctional hybrid nanostructures that can be remotely activated is an attractive strategy for a diverse range of applications ranging from electronics, cancer therapeutics, and drug delivery platforms to sophisticated biosensors. In this study, the authors examined the systematic capture of biomolecular targets onto single-walled carbon nanotubes (SWNTs), site-specific labeling with gold nanoparticles (GNPs) of three different sizes (10, 30, 60 nm), and the subsequent effects upon exposure to 1064 nm near-infrared (NIR) laser irradiation. The authors demonstrate that the SWNT-GNP hybrids containing the smallest GNPs experience greater heating and subsequent GNP release upon NIR laser irradiation compared to SWNT surfaces modified with larger 60 nm GNPs. The authors hypothesize that the greater attachment efficiency of the smaller GNPs to the biomolecules allows increased heat transduction. Therefore, it is possible to physically modify the surface of hybrid nanostructures remotely via NIR laser irradiation. It is anticipated that targeted NIR strategies will benefit from the robustness of novel material combinations, such as SWNT-GNP hybrid nanostructures, as well as interchangeable biomolecular ligands.
Show PACS
81.65.-b Surface treatments
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
61.82.Rx Nanocrystalline materials
Return to All Sections
Close

© 2013 AVS Science & Technology of Materials, Interfaces, and Processing Help | Contact
close