Search results for "monte carlo simulation"
showing 10 items of 104 documents
Noise features in InP crystals operating under static, periodic or fluctuating electric fields
2014
The results of a study concerning the intrinsic noise in low-doped n-type InP crystals operating under static, periodic or fluctuating electric fields are shown. To simulate the dynamics of electrons in the bulk, we employ a Monte Carlo approach, by taking into account the main details of band structure, scattering processes, as well as heating effects. The noise features are investigated by computing the velocity fluctuations correlation function, its spectral density and the total noise power, for different values of amplitude and frequency of the driving field. We show how the noise spectra are affected by the electric field frequency and compare their peculiarities with those exhibited …
CHANGES OF ELECTRONIC NOISE INDUCED BY OSCILLATING FIELDS IN BULK GaAs SEMICONDUCTORS
2008
A Monte Carlo study of hot-electron intrinsic noise in a n-type GaAs bulk driven by one or two mixed cyclostationary electric fields is presented. The noise properties are investigated by computing the spectral density of velocity fluctuations. An analysis of the noise features as a function of the amplitudes and frequencies of two applied fields is presented. Numerical results show that it is possible to reduce the intrinsic noise. The best conditions to realize this effect are discussed.
Monte Carlo Simulation of Harmonic Generation in GaAs structures operating under large-signal Conditions
2007
By using a multiparticles Monte Carlo technique, with a self-consistently coupled one-dimensional Poisson solver, we investigate the dependence of the nonlinear carrier dynamics in GaAs n+nn+ micro e submicro-structures operating under very intense sub-terahertz signals by: (i) the frequency and the intensity of the excitation signal and (ii) the length of the n region.
Electron dynamical response in InP semiconductors driven by fluctuating electric fields
2015
Abstract The complexity of electron dynamics in low-doped n-type InP crystals operating under fluctuating electric fields is deeply explored and discussed. In this study, we employ a multi-particle Monte Carlo approach to simulate the non-linear transport of electrons inside the semiconductor bulk. All possible scattering events of hot electrons in the medium, the main details of the band structure, as well as the heating effects, are taken into account. The results presented in this study derive from numerical simulations of the electron dynamical response to the application of a sub-Thz electric field, fluctuating for the superimposition of an external source of Gaussian correlated noise.…
Memory expansion for diffusion coefficients
1998
We present a memory expansion for macroscopic transport coefficients such as the collective and tracer diffusion coefficients ${D}_{C}$ and ${D}_{T},$ respectively. The successive terms in this expansion for ${D}_{C}$ describe rapidly decaying memory effects of the center-of-mass motion, leading to fast convergence when evaluated numerically. For ${D}_{T},$ one obtains an expansion of similar form that contains terms describing memory effects in single-particle motion. As an example we evaluate ${D}_{C}$ and ${D}_{T}$ for three strongly interacting surface systems through Monte Carlo simulations, and for a simple model diffusion system via molecular dynamics calculations. We show that the n…
Elucidating the electron transport in semiconductors via Monte Carlo simulations: An inquiry-driven learning path for engineering undergraduates
2015
Within the context of higher education for science or engineering undergraduates, we present an inquiry-driven learning path aimed at developing a more meaningful conceptual understanding of the electron dynamics in semiconductors in the presence of applied electric fields. The electron transport in a nondegenerate n-type indium phosphide bulk semiconductor is modelled using a multivalley Monte Carlo approach. The main characteristics of the electron dynamics are explored under different values of the driving electric field, lattice temperature and impurity density. Simulation results are presented by following a question-driven path of exploration, starting from the validation of the model…
Copy Number Variants and microRNAs in Autism Spectrum Disorders: a whole-genome analysis
2014
In recent years, there has been an increased interest by the scientific community on Autism Spectrum Disorders (ASDs), neurodevelopmental disorders of childhood with an incidence of about 1/160 children [1]. Different studies have indicated a strong genetic basis for autism susceptibility, also supported by the presence of autistic features in several monogenic disorders (e.g.,Fragile X syndrome, Tuberous sclerosis). Since 2007 Copy Number Variants (CNVs) were recognized as important genetic factors in ASD [2]. Studies performed so far have highlighted the pathogenic role of CNVs in terms of dosage change for protein-coding genes and few works have suggested the potential involvement of miR…
Global sensitivity analysis for micropollutant modeling by means of an urban integrated approach
2015
The paper presents the sensitivity analysis of an integrated urban water quality system by means of the global sensitivity analysis (GSA). Specifically, an home-made integrated model developed in previous studies has been modified in order to include the micropollutant assessment (namely, sulfamethoxazole - SMX). The model is able to estimate also the interactions between the three components of the system: sewer system (SS), wastewater treatment plant (WWTP) and the receiving water body (RWB). The analysis has been applied to an experimental catchment nearby Palermo (Italy): the Nocella catchment. Five scenarios each characterized by different combinations of sub-systems (i.e., SS, WWTP an…