A5052351594- Graphene research and applications
- Plasmonic and Surface Plasmon Research
- 2D Materials and Applications
- Graphene and Nanomaterials Applications
- Metamaterials and Metasurfaces Applications
- Gold and Silver Nanoparticles Synthesis and Applications
- 3D IC and TSV technologies
- Thermal Radiation and Cooling Technologies
- Electronic Packaging and Soldering Technologies
- Quantum and electron transport phenomena
- Photonic Crystals and Applications
- Diamond and Carbon-based Materials Research
- Advancements in Semiconductor Devices and Circuit Design
- ZnO doping and properties
- Chalcogenide Semiconductor Thin Films
- Topological Materials and Phenomena
- Nanowire Synthesis and Applications
- Carbon Nanotubes in Composites
- Fullerene Chemistry and Applications
- VLSI and FPGA Design Techniques
- GaN-based semiconductor devices and materials
- Photonic and Optical Devices
- Molecular Junctions and Nanostructures
- Perovskite Materials and Applications
- Ga2O3 and related materials
University of California, Berkeley
2019-2022
Purdue University West Lafayette
2011-2020
City University of Hong Kong
2007-2013
Compass Technology (China)
2008
Applied Science and Technology Research Institute
2006
McLennan Community College
2003
Dynamic switching of a plasmonic resonance may find numerous applications in subwavelength optoelectronics, spectroscopy, and sensing. Graphene shows highly tunable carrier concentration under electrostatic gating, this could provide an effective route to achieving electrical control the resonance. In Letter, we demonstrate at infrared frequencies using large-area graphene. Plasmonic structures fabricated on graphene enhance interaction incident optical field with sheet, impact is much...
Pauli blocking of interband transistions gives rise to tunable optical properties in single layer graphene (SLG). This effect is exploited a graphene-nanoantenna hybrid device where Fano resonant plasmonic nanostructures are fabricated on top sheet. The use elements enhances the interaction incident radiation with sheet and enables efficient electrical modulation resonance. We observe electrically controlled damping resonances occurring at approximately 2 μm, results verified by full-wave 3D...
Charge-transfer transitions enhance carrier generation at the interfaces of two-dimensional heterostructures.
Two new Raman modes below 100 cm^-1 are observed in twisted bilayer graphene grown by chemical vapor deposition. The two a small range of twisting angle at which the intensity G peak is strongly enhanced, indicating that these low energy and mode share same resonance enhancement mechanism, as function angle. 94 (measured with 532 nm laser excitation) assigned to fundamental layer breathing vibration (ZO (prime) mode) mediated lattice, lacks long-range translational symmetry. dependence this...
The recently proposed concept of graphene photodetectors offers remarkable properties such as unprecedented compactness, ultrabroadband detection, and an ultrafast response speed. However, owing to the low optical absorption pristine monolayer graphene, intrinsically responsivity significantly hinders development practical devices. To address this issue, numerous efforts have thus far been made enhance light-graphene interaction using plasmonic structures. These approaches, however, can be...
Corrosion of metal in biomedical devices could cause serious health problems to patients. Currently ceramics coating materials used implants can reduce corrosion some extent with limitations. Here we proposed graphene as a biocompatible protective film for potentially application. We confirmed effectively inhibits Cu surface from different biological aqueous environments. Results cell viability tests suggested that greatly eliminates the toxicity by inhibiting and reducing concentration Cu2+...
Graphene has demonstrated great potential in new-generation electronic applications due to its unique properties such as large carrier Fermi velocity, ultrahigh mobility, and high material stability. Interestingly, the structures can be further engineered multilayer graphene by introduction of a twist angle between different layers create van Hove singularities (vHSs) at adjustable binding energy. In this work, using angle-resolved photoemission spectroscopy with sub-micrometer spatial...
We report a systematic plasmonic study of twisted bilayer graphene (TBLG) - two layers stacked with twist angle. Through real-space nanoimaging TBLG single crystals wide distribution angles, we find that supports confined infrared plasmons are sensitively dependent on the At small has plasmon wavelength comparable to single-layer graphene. larger increases significantly apparently lower damping. Further analysis and modeling indicate observed twist-angle dependence in Dirac linear regime is...
We investigate electronic transport in twisted bilayer graphene (tBLG) under variable temperatures ($T$), carrier densities ($n$), and transverse magnetic fields, focusing on samples with small twist angles (\ensuremath{\theta}). These show prominent signatures associated the van Hove singularities (VHSs) superlattice-induced minigaps (SMGs). Temperature-dependent field-effect measurement shows that difference between temperature-dependent resistivity residual resistivity,...
Graphene has many promising physical properties. It been discovered that local strain in a graphene sheet can alter its conducting properties and transport gaps. is of great importance to develop scalable engineering techniques control the strains understand limit strains. Here, we present manufacturing process generate three-dimensional (3D) nanostructures thus induce sheet. This utilizes laser-induced shock pressure 3D tunable straining The size dependent critical breaking are both...
Abstract Plasmon resonances in nanopatterned single‐layer graphene nanoribbons (SL‐GNRs), double‐layer (DL‐GNRs) and triple‐layer (TL‐GNRs) are studied experimentally using ‘realistic’ samples. The existence of electrically tunable plasmons stacked multilayer was first verified by infrared microscopy. We find that the strength plasmonic resonance increases DL‐GNRs when compared to SL‐GNRs. However, further increase not observed TL‐GNRs DL‐GNRs. carried out systematic full‐wave simulations a...
Abstract We report a transient absorption (TA) imaging method for fast visualization and quantitative layer analysis of graphene GO. Forward backward on various substrates under ambient condition was imaged with speed 2 μs per pixel. The TA intensity linearly increased the number graphene. Real-time GO in vitro capability intracellular concentration e x vivo circulating blood were demonstrated. These results suggest that microscopy is valid tool study based materials.
Vertically aligned ZnO nanowire (NW) arrays have been synthesized selectively on patterned aluminum-doped zinc oxide (AZO) layer deposited silicon substrates without using any metal catalysts. The growth region was defined by conventional photolithography with an insulating template. Careful control of the types template materials and conditions allows good alignment selectivity for NW arrays. Sharp ultraviolet band-edge peak observed in photoluminescence spectra reveals optical qualities....
The discovery of graphene, a single layer covalently bonded carbon atoms, has attracted intense interest. Initial studies using mechanically exfoliated graphene unveiled its remarkable electronic, mechanical and thermal properties. There been growing need rapid development in large-area deposition film applications. Chemical vapor on copper emerged as one the most promising methods obtaining large-scale films with quality comparable to graphene. In this paper, we review synthesis...
Twisted bilayer graphene (tBLG) devices with ion gel gate dielectrics are studied using Raman spectroscopy in the twist angle regime where a resonantly enhanced G band can be observed. We observe prominent splitting and intensity quenching on when carrier density is tuned away from charge neutrality. This peak attributed to asymmetric doping two layers, which reveals individual phonon self-energy renormalization of weakly coupled layers graphene. estimate effective interlayer capacitance at...
Graphene and topological insulators (TI) possess two-dimensional (2D) Dirac fermions with distinct physical properties. Integrating these two materials in a single device creates interesting opportunities for exploring new physics of interacting massless fermions. Here we report on practical route to experimental fabrication graphene–Sb2Te3 heterostructure. The graphene–TI heterostructures are prepared by using dry transfer chemical-vapor-deposition grown graphene film. ARPES measurements...
Graphene field effect transistors (GFETs) fabricated by chemical vapor deposition graphene deposited onto SiC substrates exhibit sensitivity to broadband visible light. The hysteretic nature of this GFET type was studied utilizing a new current-voltage measurement technique in conjunction with current-time measurements. This method accounts for changes response and enables transfer measurements that can be attributed fixed gate voltages. hysteresis is shown consistent electrochemical p-type...
Well-aligned ZnO nanorod arrays were synthesized noncatalytically on a conducting aluminum-doped zinc oxide (AZO) buffer layer. The synthesis uses no metal catalyst and is cost-effective. layer facilitates the growth of vertically aligned nanorods; furthermore, we demonstrate that optical properties resulting nanorods are closely correlated to crystallographic quality Spatially resolved cathodoluminescence microscopy measurements show for nonideal layers improves along [0001] direction...