Simulation of longitudinal instabilities in filamentary current flow during low‐temperature impurity breakdown in semiconductors

Abstract

Nonlinear semiconductor transport simulations based on the WIAS-TeSCA code are presented. Various regimes of lowtemperature breakdown and current filamentation in n-GaAs are investigated using a drift-diffusion model with nonlinear generation-recombination kinetics. Nonlinear charge density waves are found in two-dimensional simulations of a point contact geometry with and without an additional perpendicular magnetic field. The numerical simulations of the nonlinear spatio-temporal dynamics are complemented by a linear stability analysis which reveals the possibility of undamped longitudinal fluctuations in the filamentary regime.

Two-level model of oscillating electric-field-induced current instability and chaos in n-GaAs

“…On the upper branch, the drift velocity increases obviously as a result of the sharp increase of the electron temperature and density. Since T e can be determined from the energy balance equation equation (11) or (12) and ν is related to the electric field by GR rate equations (1) and (2), our μ BH in equation ( 9) used to express the enhancement of the mobility on the upper branch of the n(E) characteristic is dependent on the electric field implicitly. Thus solving the coupled differential equations (1), (2), (5), and (12) enables us to examine the cross-over instability for n-type GaAs due to the effects from the electric field E including the oscillating ac field, our present main interest, and the carrier temperature T e variation.…”

“…There exist quite a few experimental and theoretical works on this subject for different types of semiconductors. For example, instabilities observed and studied in high purity n-GaAs at 4.2 K include the driven chaos induced by periodically modulated bias voltage [1][2][3][4], that by weak perpendicular and/or longitudinal magnetic fields [5][6][7][8][9][10][11][12][13], and the self-generated chaos which is observed under dc conditions and is broadly independent of external conditions [14][15][16][17][18][19][20][21][22][23][24]. We have discussed the magnetic effects in our previous works [25][26][27].…”