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We investigate the effects of electron and acoustic phonon confinements on the low-field electron mobility of thin, gated, square silicon nanowires (SiNWs), surrounded by SiO2. We employ a self-consistent Poisson–Schrödinger–Monte Carlo solver that accounts for scattering due to acoustic phonons (confined and bulk), intervalley phonons, and the Si/SiO2 surface roughness. The wires considered have cross sections between 3×3 and 8×8 nm2. For larger wires, the dependence of the mobility on the transverse field from the gate is pronounced, as expected. At low transverse fields, where phonon scattering dominates, scattering from confined acoustic phonons results in about a 10% decrease in the mobility with respect to the bulk phonon approximation. As the wire cross section decreases, the electron mobility drops because the detrimental increase in both electron-acoustic phonon and electron-surface roughness scattering rates overshadows the beneficial volume inversion and subband modulation. For wires thinner than 5×5 nm2, surface roughness scattering dominates regardless of the transverse field applied and leads to a monotonic decrease in the electron mobility with decreasing SiNW cross section. [ABSTRACT FROM AUTHOR]

We characterize the linear and nonlinear electron transport in quantum point contacts (QPCs) realized by a hybrid combination of etching and gating. We demonstrate that the strong electron confinement generated through this hybrid QPC process results in quantized subbands with a large energy separation, leading to the observation of robust one-dimensional quantum-transport effects. Measurements of the nonlinear differential conductance reveal an unexpected bunching of curves at 0.20-0.25×2e2/h, rather than at the expected value of 0.5×2e2/h. Application of a simple analytical model indicates that this bunching is associated with the highly asymmetric manner in which the source-drain voltage is dropped across the QPC near pinch-off and under nonequilibrium conditions. [ABSTRACT FROM AUTHOR]

Presents a Monte Carlo simulation of electron transport in alternating-current thin film electroluminescent (ACTFEL) devices. Approaches used to describe ACTFEL electronic transport in the high-field regime; Description of the Monte Carlo simulation method; Scattering rates for various scattering mechanisms as a function of energy for electron transport.

Impact ionization plays a crucial role for electron transport in wide-bandgap semiconductors at high electric fields. Therefore, a realistic band structure has to be used in calculations of the microscopic scattering rate, as well as high field quantum corrections such as the intercollisional field effect. Here we consider both, and evaluate the impact ionization rate for wide-bandgap materials such as ZnS. A pronounced softening of the impact ionization threshold is obtained, as found earlier for materials like Si and GaAs. This field dependent impact ionization rate is included within a full-band ensemble Monte Carlo simulation of high field transport in ZnS. Although the impact ionization rate itself is strongly affected, little effect is observed on measurable quantities such as the impact ionization coefficient or the electron distribution function itself. [ABSTRACT FROM AUTHOR]