Ensemble Monte Carlo with Poisson solver for the study of current fluctuations in homogeneous GaAs structures

Abstract

An analysis of current fluctuations in homogeneous N-type GaAs structures of different lengths and doping concentrations is presented. The study is performed coupling self-consistently a Poisson solver to a many-particle Monte Carlo simulation. The autocorrelation functions and the spectral density of current fluctuations are calculated, dividing them into different contributions that allow one to analyze several sources of noise. A qualitative analysis of shot noise is made. Different behaviors of current fluctuations are found among the different structures; these are interpreted in terms of the microscopic processes occurring inside them. For high values of impurity concentration (1017 cm−3), the coupling between fluctuations in the electric field and in carrier velocity is found to be an important source of noise.