Time-Resolved Spatial Structures of Periodically-Driven Current Filament in n-GaAs

抄録

Time-resolved spatial structures of a current density filament in n-GaAs have been investigated under a dc+ac drive voltage V_dc+V_acsin 2π f_dt at 4.2 K. With a sinusoidal drive of V_dc=0.95 V, V_ac=388 mV and f_d=100 kHz, we observe an S-shaped I-V curve caused by the impact ionization avalanche of neutral shallow donors and subsequent formation of a current density filament. Evolution of the current-density filament was studied by the time-resolved measurements of the photoluminescence quench-patterns. A new finding is the Turing bifurcation observed at around the breakdown voltage.