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We present a novel method for device noise measurement, based on a two-channel cross-correlation technique and a direct 'in situ' measurement of the transimpedance of the device under test (DUT), which allows improved accuracy with respect to what is available in the literature, in particular when the DUT is a nonlinear device. Detailed analytical expressions for the total residual noise are derived, and an experimental investigation of the increased accuracy provided by the method is performed. [ABSTRACT FROM AUTHOR]

We present numerical simulations of high field transport in both suspended and deposited armchair graphene nanoribbon (A-GNR) on HfO2 substrate. Drift velocity in suspended GNR does not saturate at high electric field (F), but rather decreases, showing a maximum for F ≈ 10 kV/cm. Deposition on HfO2 strongly degrades the drift velocity by up to a factor ≈10 with respect to suspended GNRs in the low-field regime, whereas at high fields, drift velocity approaches the intrinsic value expected in suspended GNRs. Even in the assumption of perfect edges, the obtained mobility is far behind what expected in two-dimensional graphene, and is further reduced by surface optical phonons. [ABSTRACT FROM AUTHOR]

We investigate the low-field phonon-limited mobility in armchair graphene nanoribbons (GNRs) using full-band electron and phonon dispersion relations. We show that lateral confinement suppresses the intrinsic mobility of GNRs to values typical of common bulk semiconductors, and very far from the impressive experiments on two-dimensional graphene. 1 nm-wide suspended GNRs exhibit a mobility close to 500 cm2/V s at room temperature, whereas 1 nm-wide GNRs deposited on HfO2 exhibit a mobility of 60 cm2/V s due to surface phonons. We also show the occurrence of polaron formation, leading to band gap renormalization of ≈118 meV for 1-nm-wide armchair GNRs. [ABSTRACT FROM AUTHOR]

We predict shot noise enhancement in defect-free carbon nanotube field-effect transistors through a numerical investigation based on the self-consistent solution of the Poisson and Schrödinger equations within the nonequilibrium Green’s functions formalism, and on a Monte Carlo approach to reproduce injection statistics. Noise enhancement is due to the correlation between trapping of holes from the drain into quasibound states in the channel and thermionic injection of electrons from the source, and can lead to an appreciable Fano factor of 1.22 at room temperature. [ABSTRACT FROM AUTHOR]

In this letter, we investigate the observed dependence of the programming window of silicon-on-insulator (SOI) nanocrystal memories on the width of the channel. Indeed, experiments show that the obtained threshold voltage shift after programming strongly increases with decreasing channel width. We show that such behavior is due to the preferential injection of electrons, during the program operation, from regions close to the edges of the SOI channel, where the electric field is stronger. As a consequence, charge is mostly stored in the dots in the oxide region surrounding the edges, and therefore is more and more effective as the channel width is decreased. Our conjecture is verified through dedicated three-dimensional simulations and checked against other mechanisms proposed in the literature. [ABSTRACT FROM AUTHOR]

We present a code for the quantum simulation of ballistic metal-oxide-semiconductor field effect transistors (MOSFETs) in two dimensions, which has been applied to the simulation of a so-called “well-tempered” MOSFET with channel length of 25 nm. Electron confinement at the Si/SiO[sub 2] interface and effective mass anisotropy are properly taken into account. In the assumption of negligible phonon scattering in nanoscale devices, transport is assumed to be purely ballistic. We show that our code can provide the relevant direct-current characteristics of the device by running on a simple high-end personal computer, and can be a useful tool for the extraction of physics-based compact models of nanoscale MOSFETs. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]