PERIODICALLY-DRIVEN PATTERN DYNAMICS OF A CURRENT FILAMENT INDUCED BY IMPACT IONIZATION IN N-GAAS

摘要

Periodically-driven pattern dynamics of a current filament formed during impact ionization avalanche have been investigated in n-GaAs at 4.2 K by means of the scanning laser microscopy and the measurements of the photoluminescence quench-patterns by using a CCD camera. Preliminary measurements under a pulse voltage indicate that a rudimentary filament can be formed within 900 ns. Under the periodically-driven regime with an applied bias Vo + V-ac sin(2 pi f(0)t), the filamentary current exhibits a period doubling route to chaos when the driving amplitude V-ac is increased. Dynamical phase transition from a driven-breathing mode to bulk-dominated oscillation mode is found at the first bifurcation point of the period doubling. Details of the driven-breathing mode of the filament have been argued from the photoluminescence quench-patterns. [References: 10]