ABSTRACT
As a conventional and powerful method to visualize the current density filament, Eberle et al. have shown a visualization technique by measuring the photoluminescence (PL) quench-patterns [3]. By the PL method, Aoki [4-8] has investigated the nucleation process of a current density filament [4] and also the nonlinear dynamics of the filament during the current instability under the magnetic fields in n-GaAs [5, 6]. Very recently, the author has found that the PL pattern image under a short pulsed voltage can be seen as a bright pattern inside the filament or along the filament boundaries in an n-GaAs Corbino disk. [7, 8] The anomalous brightening of the PL intensity observed during the impact ionization avalanche is a quite novel phenomenon because all of the luminescent
centers (neutral donors and bound excitons) have been considered to be completely impact-ionized in the postbreakdown regime. In this paper, the spatiotemporal imaging of the current density filaments in an n-GaAs Corbino disk has been investigated in detail by the PL method. Our purpose is to find the origin of the anomalous brightening of the PL intensity inside the current density filaments.
