Spatiotemporal behavior of localized current filaments in p-n-p-n diodes: Numerical calculations and comparison with experimental results

A two-component evolution equation of reaction-diffusion type derived recently to describe experimental results on the self-organization of current-density filaments in silicon p-n-p-n diodes has been solved numerically. By using physically reasonable parameters and applying different boundary conditions, good qualitative agreement with experimental results is obtained. In particular, the following bifurcation scenario obtained by increasing the external driving voltage in the experiment can be reproduced in the calculations: stationary homogeneous current-density distribution leads to static current filament leads to rocking current filament leads to traveling current filament. Furthermore, it is shown that a period-doubling cascade of integral system variables, as, e.g., the device voltage, strongly correlates with the spatiotemporal filament motion which undergoes the same period-doubling route. Even quantitative agreement between numerical and experimental results could be achieved to some extent.