Steady-state properties of lock-on current filaments in GaAs

Abstract

Abstract--Collective impact ionization has been used to exT1ain lock-on in semi-insulating GaAs under highvohage bias. W7ehave used this theory to study some of the steady state properties of lock-on current filaments. In steady state, the heat gained from the field is exactly compensated by the cooling due to phonon scattering. In the simplest approximation, the carrier distribution approaches a quasi-equ~lbrium Ma.xwell-Boltzmann distribution. In this repom we examine the validity of this approximation. \Ye fmd that this approximation leads to a filament carrier density which is much lower than the high density needed to achieve a quasiequilibrium distribution. Further work on this subject is in progress.

Modeling of GaAs photoconductive switches

“…Zi=V.k(T).VT+H (8) where p is the density and c is the specific heat capacity of the semiconductor material, H and /c(T) represent the locally generated heat and the thermal conductivity respectively. This completes the coupled nonlinear parabolic/elliptic equations system.…”

Carrier accumulation effect in PCSS

“…However, the principle of the nonlinear mode of PCSS has not been understood quite well [4] . There are some models to try to explain it [5 7] , but none is perfect.…”

Optical absorption mechanism of GaAs photoconductive semiconductor switch

“…In the nonlinear mode, the carrier concentration increases not only through the absorption of the triggering optical pulse but also by gain mechanisms. Although several models have been proposed to explain the nonlinear mode, [9][10][11][12] the physical mechanism of the nonlinear mode is still not well understood until now. 13) As the seed carrier of avalanche, photogenerated carrier density is an important parameter for the carrier multiplication of the nonlinear PCSS.…”

“…Thus far, the avalanche mechanism has not been fully understood and is an important area of study. [11][12][13] In the nonlinear mode, owing to carrier avalanche multiplication, the number of photogenerated carriers is not equal to that of output charges, and the output charge increases with the increase in bias voltage.…”