Browse
Submit Data
Databases
API
Help

Dataset Information

27 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Bandgap opening by patterning graphene.

ABSTRACT: Owing to its remarkable electronic and transport properties, graphene has great potential of replacing silicon for next-generation electronics and optoelectronics; but its zero bandgap associated with Dirac fermions prevents such applications. Among numerous attempts to create semiconducting graphene, periodic patterning using defects, passivation, doping, nanoscale perforation, etc., is particularly promising and has been realized experimentally. However, despite extensive theoretical investigations, the precise role of periodic modulations on electronic structures of graphene remains elusive. Here we employ both the tight-binding modeling and first-principles electronic structure calculations to show that the appearance of bandgap in patterned graphene has a geometric symmetry origin. Thus the analytic rule of gap-opening by patterning graphene is derived, which indicates that if a modified graphene is a semiconductor, its two corresponding carbon nanotubes, whose chiral vectors equal graphene's supercell lattice vectors, are both semimetals.

SUBMITTER: Dvorak M

PROVIDER: S-EPMC3724180 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Bandgap opening by patterning graphene.

Dvorak Marc M Oswald William W Wu Zhigang Z

Scientific reports 20130101

Owing to its remarkable electronic and transport properties, graphene has great potential of replacing silicon for next-generation electronics and optoelectronics; but its zero bandgap associated with Dirac fermions prevents such applications. Among numerous attempts to create semiconducting graphene, periodic patterning using defects, passivation, doping, nanoscale perforation, etc., is particularly promising and has been realized experimentally. However, despite extensive theoretical investiga ...[more]

PMID: 23887253

Similar Datasets

Ultrafast growth of nanocrystalline graphene films by quenching and grain-size-dependent strength and bandgap opening.

Project description:Nanocrystallization is a well-known strategy to dramatically tune the properties of materials; however, the grain-size effect of graphene at the nanometer scale remains unknown experimentally because of the lack of nanocrystalline samples. Here we report an ultrafast growth of graphene films within a few seconds by quenching a hot metal foil in liquid carbon source. Using Pt foil and ethanol as examples, four kinds of nanocrystalline graphene films with average grain size of ~3.6, 5.8, 8.0, and 10.3?nm are synthesized. It is found that the effect of grain boundary becomes more pronounced at the nanometer scale. In comparison with pristine graphene, the 3.6?nm-grained film retains high strength (101?GPa) and Young's modulus (576?GPa), whereas the electrical conductivity is declined by over 100 times, showing semiconducting behavior with a bandgap of ~50?meV. This liquid-phase precursor quenching method opens possibilities for ultrafast synthesis of typical graphene materials and other two-dimensional nanocrystalline materials.

| S-EPMC6813332 | biostudies-literature

Large bandgap of pressurized trilayer graphene.

Project description:Graphene-based nanodevices have been developed rapidly and are now considered a strong contender for postsilicon electronics. However, one challenge facing graphene-based transistors is opening a sizable bandgap in graphene. The largest bandgap achieved so far is several hundred meV in bilayer graphene, but this value is still far below the threshold for practical applications. Through in situ electrical measurements, we observed a semiconducting character in compressed trilayer graphene by tuning the interlayer interaction with pressure. The optical absorption measurements demonstrate that an intrinsic bandgap of 2.5 ± 0.3 eV could be achieved in such a semiconducting state, and once opened could be preserved to a few GPa. The realization of wide bandgap in compressed trilayer graphene offers opportunities in carbon-based electronic devices.

| S-EPMC6511052 | biostudies-literature

Silicene nanomeshes: bandgap opening by bond symmetry breaking and uniaxial strain.

Project description:Based on the first-principles calculations, we have investigated in detail the bandgap opening of silicene nanomeshes. Different to the mechanism of bandgap opening induced by the sublattice equivalence breaking, the method of degenerate perturbation through breaking the bond symmetry could split the π-like bands in the inversion symmetry preserved silicene nanomeshes, resulting into the πa1 - πa2 and πz1 - πz2 band sets with sizable energy intervals. Besides the bandgap opening in the nanomeshes with Dirac point being folded to Γ point, the split energy intervals are however apart away from Fermi level to leave the semimetal nature unchanged for the other nanomeshes with Dirac points located at opposite sides of Γ point as opposite pseudo spin wave valleys. A mass bandgap could be then opened at the aid of uniaxial strain to transfer the nanomesh to be semiconducting, whose width could be continuously enlarged until reaching its maximum Emax. Moreover, the Emax could also be tuned by controlling the defect density in silicene nanomeshes. These studies could contribute to the understanding of the bandgap engineering of silicene-based nanomaterials to call for further investigations on both theory and experiment.

| S-EPMC4748269 | biostudies-other

NLL-Assisted Multilayer Graphene Patterning.

Project description:The range of applications of diverse graphene-based devices could be limited by insufficient surface reactivity, unsatisfied shaping, or null energy gap of graphene. Engineering the graphene structure by laser techniques can adjust the transport properties and the surface area of graphene, providing devices of different nature with a higher capacitance. Additionally, the created periodic potential and appearance of the active external/inner/edge surface centers determine the multifunctionality of the graphene surface and corresponding devices. Here, we report on the first implementation of nonlinear laser lithography (NLL) for multilayer graphene (MLG) structuring, which offers a low-cost, single-step, and high-speed nanofabrication process. The NLL relies on the employment of a high repetition rate femtosecond Yb fiber laser that provides generation of highly reproducible, robust, uniform, and periodic nanostructures over a large surface area (1 cm2/15 s). NLL allows one to obtain clearly predesigned patterned graphene structures without fabrication tolerances, which are caused by contacting mask contamination, polymer residuals, and direct laser exposure of the graphene layers. We represent regularly patterned MLG (p-MLG) obtained by the chemical vapor deposition method on an NLL-structured Ni foil. We also demonstrate tuning of chemical (wettability) and electro-optical (transmittance and sheet resistance) properties of p-MLG by laser power adjustments. In conclusion, we show the great promise of fabricated devices, namely, supercapacitors, and Li-ion batteries by using NLL-assisted graphene patterning. Our approach demonstrates a new avenue to pattern graphene for multifunctional device engineering in optics, photonics, and bioelectronics.

| S-EPMC5830696 | biostudies-literature

One-dimensional confinement and width-dependent bandgap formation in epitaxial graphene nanoribbons.

Project description:The ability to define an off state in logic electronics is the key ingredient that is impossible to fulfill using a conventional pristine graphene layer, due to the absence of an electronic bandgap. For years, this property has been the missing element for incorporating graphene into next-generation field effect transistors. In this work, we grow high-quality armchair graphene nanoribbons on the sidewalls of 6H-SiC mesa structures. Angle-resolved photoelectron spectroscopy (ARPES) and scanning tunneling spectroscopy measurements reveal the development of a width-dependent semiconducting gap driven by quantum confinement effects. Furthermore, ARPES demonstrates an ideal one-dimensional electronic behavior that is realized in a graphene-based environment, consisting of well-resolved subbands, dispersing and non-dispersing along and across the ribbons respectively. Our experimental findings, coupled with theoretical tight-binding calculations, set the grounds for a deeper exploration of quantum confinement phenomena and may open intriguing avenues for new low-power electronics.

| S-EPMC7733518 | biostudies-literature

Lift-Off Assisted Patterning of Few Layers Graphene.

Project description:Graphene and 2D materials have been exploited in a growing number of applications and the quality of the deposited layer has been found to be a critical issue for the functionality of the developed devices. Particularly, Chemical Vapor Deposition (CVD) of high quality graphene should be preserved without defects also in the subsequent processes of transferring and patterning. In this work, a lift-off assisted patterning process of Few Layer Graphene (FLG) has been developed to obtain a significant simplification of the whole transferring method and a conformal growth on micrometre size features. The process is based on the lift-off of the catalyst seed layer prior to the FLG deposition. Starting from a SiO2 finished Silicon substrate, a photolithographic step has been carried out to define the micro patterns, then an evaporation of Pt thin film on Al2O3 adhesion layer has been performed. Subsequently, the Pt/Al2O3 lift-off step has been attained using a dimethyl sulfoxide (DMSO) bath. The FLG was grown directly on the patterned Pt seed layer by Chemical Vapor Deposition (CVD). Raman spectroscopy was applied on the patterned area in order to investigate the quality of the obtained graphene. Following the novel lift-off assisted patterning technique a minimization of the de-wetting phenomenon for temperatures up to 1000 °C was achieved and micropatterns, down to 10 µm, were easily covered with a high quality FLG.

| S-EPMC6631601 | biostudies-literature

Patterning Graphene Film by Magnetic-assisted UV Ozonation.

Project description:Developing an alternative method for fabricating microscale graphene patterns that overcomes the obstacles of organic contamination, linewidth resolution, and substrate damaging is paramount for applications in optoelectronics. Here we propose to pattern chemical vapor deposition grown graphene film through a stencil mask by magnetic-assisted ultraviolet (UV) ozonation under irradiation of a xenon excimer lamp. In this process, the paramagnetic oxygen molecules and photochemically generated oxygen radicals are magnetized and attracted in an inhomogenous external magnetic field. As a consequence, their random motions convert into directional, which can greatly modify or enhance the quality of graphene patterns. Using a ferromagnetic steel mask, an approximately vertical magnetic-field-assisted UV ozonation (BZ = 0.31 T, ∇BZ = 90 T · m-1) has a capability of patterning graphene microstructures with a line width of 29 μm and lateral under-oxidation less than 4 μm. Our approach is applicable to patterning graphene field-effect transistor arrays, and it can be a promising solution toward resist-free, substrate non-damaging, and cost effective microscale patterning of graphene film.

| S-EPMC5395948 | biostudies-literature

Dirac cone move and bandgap on/off switching of graphene superlattice.

Project description:Using the density functional theory with generalized gradient approximation, we have studied in detail the cooperative effects of degenerate perturbation and uniaxial strain on bandgap opening in graphene. The uniaxial strain could split π bands into πa and πz bands with an energy interval Es to move the Dirac cone. The inversion symmetry preserved antidot would then further split the πa (πz) bands into πa1 (πz1) and πa2 (πz2) bands with an energy interval Ed, which accounts for the bandgap opening in a kind of superlattices with Dirac cone being folded to Γ point. However, such antidot would not affect the semimetal nature of the other superlattices, showing a novel mechanism for bandstructure engineering as compared to the sublattice-equivalence breaking. For a superlattice with bandgap of ~Ed opened at Γ point, the Es could be increased by strengthening strain to close the bandgap, suggesting a reversible switch between the high velocity properties of massless Fermions attributed to the linear dispersion relation around Dirac cone and the high on/off ratio properties associated with the sizable bandgap. Moreover, the gap width actually could be continuously tuned by controlling the strain, showing attractive application potentials.

| S-EPMC4702062 | biostudies-other

Boron-Doped Reduced Graphene Oxide with Tunable Bandgap and Enhanced Surface Plasmon Resonance.

Project description:Graphene and its hybrids are being employed as potential materials in light-sensing devices due to their high optical and electronic properties. However, the absence of a bandgap in graphene limits the realization of devices with high performance. In this work, a boron-doped reduced graphene oxide (B-rGO) is proposed to overcome the above problems. Boron doping enhances the conductivity of graphene oxide and creates several defect sites during the reduction process, which can play a vital role in achieving high-sensing performance of light-sensing devices. Initially, the B-rGO is synthesized using a modified microwave-assisted hydrothermal method and later analyzed using standard FESEM, FTIR, XPS, Raman, and XRD techniques. The content of boron in doped rGO was found to be 6.51 at.%. The B-rGO showed a tunable optical bandgap from 2.91 to 3.05 eV in the visible spectrum with an electrical conductivity of 0.816 S/cm. The optical constants obtained from UV-Vis absorption spectra suggested an enhanced surface plasmon resonance (SPR) response for B-rGO in the theoretical study, which was further verified by experimental investigations. The B-rGO with tunable bandgap and enhanced SPR could open up the solution for future high-performance optoelectronic and sensing applications.

| S-EPMC7465222 | biostudies-literature

Narrow bandgap oxide nanoparticles coupled with graphene for high performance mid-infrared photodetection.

Project description:The pursuit of optoelectronic devices operating in the mid-infrared regime is driven by both fundamental interests and envisioned applications ranging from imaging, sensing to communications. Despite continued achievements in traditional semiconductors, notorious obstacles such as the complicated growth processes and cryogenic operation preclude the usage of infrared detectors. As an alternative path towards high-performance photodetectors, hybrid semiconductor/graphene structures have been intensively explored. However, the operation bandwidth of such photodetectors has been limited to visible and near-infrared regimes. Here we demonstrate a mid-infrared hybrid photodetector enabled by coupling graphene with a narrow bandgap semiconductor, Ti2O3 (Eg?=?0.09 eV), which achieves a high responsivity of 300?A?W-1 in a broadband wavelength range up to 10?µm. The obtained responsivity is about two orders of magnitude higher than that of the commercial mid-infrared photodetectors. Our work opens a route towards achieving high-performance optoelectronics operating in the mid-infrared regime.

| S-EPMC6191432 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data