Effects of electric field and device size on the electron velocity in p-i-n GaAs semiconductor

Abstract

This paper introduces the investigation of the influence of electric field and device size on the drift velocity of electrons in GaAs semiconductor using ensemble Monte Carlo simulation method under limited size conditions. We employed a GaAs diode device model with p-i-n structure, consisting of p-type and n-type semiconductor layers with uniform size of 20 nm, and a variable-sized intrinsic (i) semiconductor layer in between. We show that in the absence of external electric field, the damped velocity will diminish as the size of the (i) layer ranges from 100 nm to 800 nm. And the damped oscillation period of the electron velocity is a linear function of the device size. Additionally, by examining the maximum value of electron velocity under the influence of an external electric field, our observed results are consistent with those reported by Saraniti et al. (2002) [22] in low electric field below 50 kV/cm; while at higher electric fields, the maximum velocity gradually increased to a saturation value. Furthermore, the maximum velocity vmax is found to follow a simple logarithmic law as a function of i-layer size S as vmax=aln⁡(bS). The coefficients of this relation equation were derived using least-square approximation technique yielding a high determination coefficient R2 up to 0.998.