David K. Ferry

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We have studied the transport properties of graphene transistors in different solvents with dielectric constant varying over 2 orders of magnitude. Upon increasing the dielectric constant, the carrier mobility increases up to 3 orders of magnitude and reaches approximately 7 x 10(4) cm(2)/v.s at the dielectric constant of approximately 47. This mobility(More)
This brief aims to show the effects of threading edge dislocations on the dc and RF performance of GaN highelectron mobility transistor (HEMT) devices. A state-of-the-art high-frequency and high-power HEMT was investigated with our full-band cellular Monte Carlo (CMC) simulator, which includes the full details of the band structure and the phonon spectra. A(More)
The theoretical understanding of electron transport in graphene and graphene nanoribbons is reviewed, emphasizing the help provided by atomic pseudopotentials (self-consistent and empirical) in determining not only the band structure but also other fundamental transport parameters such as electron-phonon matrix elements and line-edge roughness scattering.(More)
We study the transport of carriers in intrinsic graphene by means of an ensemble Monte Carlo technique. Scattering by acoustic and optical phonons dominates the transport. We find that velocity 'saturation' sets in at relatively low values of the electric field, but that the value is dependent upon the carrier density. Velocity overshoot is also observed to(More)
Recent studies have shown that a high K dielectric solvent screens the impurities for room temperature transport in graphene and the mobility has been found to increase by orders of magnitude. This gives what is probably the intrinsic, phonon limited mobility at room temperature, and we have confirmed this with simulation. Mobility as high as 44 000 cm(2)(More)
We have carried out Hall measurement on back-gated graphene field effect transistors (FET) with and without a top dielectric medium. The gate efficiency increases by up to 2 orders of magnitude in the presence of a high κ top dielectric medium, but the mobility does not change significantly. Our measurement further shows that the back-gate capacitance is(More)
We study electronic transport in quantum-dot structures made of graphene. Focusing on the rectangular dot geometry and utilizing the non-equilibrium Green's function to calculate the transmission in the tight-binding framework, we find significant fluctuations in the transmission as a function of the electron energy. The fluctuations are correlated with the(More)
The role of synchronism in systems of threshold elements (such as neural networks) is examined. Some important differences between synchronous and asynchronous systems are outlined. In particular, important restrictions on limit cycles are found in asynchronous systems along with multi-frequency oscillations which do not appear in synchronous systems. The(More)