A5023415293- Graphene research and applications
- Quantum and electron transport phenomena
- 2D Materials and Applications
- Carbon Nanotubes in Composites
- Topological Materials and Phenomena
- Molecular Junctions and Nanostructures
- Thermal properties of materials
- Mechanical and Optical Resonators
- Physics of Superconductivity and Magnetism
- Diamond and Carbon-based Materials Research
- Surface and Thin Film Phenomena
- Bladder and Urothelial Cancer Treatments
- Plasmonic and Surface Plasmon Research
- Advanced Thermoelectric Materials and Devices
- Advancements in Battery Materials
- Electronic and Structural Properties of Oxides
- MXene and MAX Phase Materials
- Nanowire Synthesis and Applications
- Thermal Radiation and Cooling Technologies
- Photonic and Optical Devices
- Semiconductor materials and devices
- Chalcogenide Semiconductor Thin Films
- Musculoskeletal pain and rehabilitation
- Pain Management and Treatment
- Perovskite Materials and Applications
Harvard University
2016-2025
Harvard University Press
2000-2025
International Spine, Pain & Performance
2014-2024
Society for Vascular Surgery
2024
Christiana Hospital
2012-2024
Pain Management Institute
2022-2024
Grady Memorial Hospital
2023-2024
QuTech
2024
Bryn Mawr Hospital
2012-2024
University of California, Los Angeles
2021-2024
We investigate electronic transport in lithographically patterned graphene ribbon structures where the lateral confinement of charge carriers creates an energy gap near neutrality point. Individual layers are contacted with metal electrodes and into ribbons varying widths different crystallographic orientations. The temperature dependent conductance measurements show larger gaps opening for narrower ribbons. sizes these investigated by measuring non-linear response regime at low...
The thermal conductivity and thermoelectric power of a single carbon nanotube were measured using microfabricated suspended device. observed is more than 3000 W/K m at room temperature, which 2 orders magnitude higher the estimation from previous experiments that used macroscopic mat samples. temperature dependence nanotubes exhibits peak 320 K due to onset umklapp phonon scattering. shows linear with value 80 microV/K temperature.
The quantum Hall effect (QHE), one example of a phenomenon that occur on truly macroscopic scale, has been attracting intense interest since its discovery in 1980 and helped elucidate many important aspects physics. It also led to the establishment new metrological standard, resistance quantum. Disappointingly, however, QHE could only have observed at liquid-helium temperatures. Here, we show graphene - single atomic layer carbon can reliably be measured even room temperature, which is not...
Heterostructures based on layering of two-dimensional (2D) materials such as graphene and hexagonal boron nitride represent a new class electronic devices. Realizing this potential, however, depends critically the ability to make high-quality electrical contact. Here, we report contact geometry in which metalize only 1D edge 2D layer. In addition outperforming conventional surface contacts, edge-contact allows complete separation layer assembly metallization processes. heterostructures,...
The thermal conductivities of individual single crystalline intrinsic Si nanowires with diameters 22, 37, 56, and 115 nm were measured using a microfabricated suspended device over temperature range 20–320 K. Although the had well-defined order, conductivity observed was more than two orders magnitude lower bulk value. strong diameter dependence in ascribed to increased phonon-boundary scattering possible phonon spectrum modification.
We report variation of the work function for single and bilayer graphene devices measured by scanning Kelvin probe microscopy (SKPM). By use electric field effect, can be adjusted as gate voltage tunes Fermi level across charge neutrality point. Upon biasing device, surface potential map obtained SKPM provides a reliable way to measure contact resistance individual electrodes contacting graphene.
The resistivity of ultraclean suspended graphene is strongly temperature (T) dependent for 5<T<240 K. At T-5 K transport near-ballistic in a device approximately 2 microm dimension and mobility 170,000 cm2/V s. large carrier density, n>0.5 x 10(11) cm(-2), the increases with increasing T linear above 50 K, suggesting scattering from acoustic phonons. T=240 120,000 s, higher than any known semiconductor. charge neutral point we observe nonuniversal conductivity that decreases decreasing T,...
Gate-modulated low-temperature Raman spectra reveal that the electric field effect (EFE), pervasive in contemporary electronics, has marked impacts on long-wavelength optical phonons of graphene. The EFE this two-dimensional honeycomb lattice carbon atoms creates large density modulations carriers with linear dispersion (known as Dirac fermions). Our display interactions vibrations these unusual carriers. changes phonon frequency and linewidth demonstrate optically particle-hole symmetry...
Nanoscale electromechanical systems-nanotweezers-based on carbon nanotubes have been developed for manipulation and interrogation of nanostructures. Electrically conducting mechanically robust were attached to independent electrodes fabricated pulled glass micropipettes. Voltages applied the closed opened free ends nanotubes, this response was simulated quantitatively using known nanotweezer structure nanotube properties. The mechanical capabilities nanotweezers demonstrated by grabbing...
Oxygen Control of Graphene Growth The growth graphene on copper surfaces through the decomposition hydrocarbons such as methane can result in a wide variety crystal domain sizes and morphologies. Hao et al. (p. 720 , published online 24 October; see cover) found that presence surface oxygen could limit number nucleation sites allowed centimeter-scale domains to grow diffusion-limited mechanism. electrical conductivity was comparable exfoliated graphene.
Atomically thin forms of layered materials, such as conducting graphene, insulating hexagonal boron nitride (hBN), and semiconducting molybdenum disulfide (MoS2), have generated great interests recently due to the possibility combining diverse atomic layers by mechanical "stacking" create novel materials devices. In this work, we demonstrate field-effect transistors (FETs) with MoS2 channels, hBN dielectric, graphene gate electrodes. These devices show mobilities up 45 cm(2)/Vs operating...
The conductivity of graphene samples with various levels disorder is investigated for a set specimens mobility in the range 1-20x10(3) cm2/V sec. Comparing experimental data theoretical transport calculations based on charged impurity scattering, we estimate that concentration varies from 2-15x10(11) cm(-2). In low carrier density limit, exhibits values 2-12e2/h, which can be related to residual induced by inhomogeneous charge distribution samples. shape curves indicates high contain some...
We report on the temperature dependent electron transport in graphene at different carrier densities $n$. Employing an electrolytic gate, we demonstrate that $n$ can be adjusted up to 4$\times10^{14}$cm$^{-2}$ for both electrons and holes. The measured sample resistivity $\rho$ increases linearly with $T$ high limit, indicating a quasi-classical phonon distribution is responsible scattering. As decreases, decreases more rapidly following $\rho (T) \sim T^{4}$. This low behavior described by...