Progression of an excess-carrier pulse in Zn-compensated P-doped Si exposed to an electric field close to the recombination-wave threshold

The progress of convective current instability associated with slow recombination waves in Zn-compensated P-doped Si is studied experimentally. The drift is examined of an excess-carrier pulse in specimens exposed to an electric field close to the recombination-wave threshold, the pulse being created by intrinsic photoconductivity. It is established that the pulse travels in the direction of the drift of long-lived carriers, electrons. The speed of the pulse is found to agree with a predicted value to within an order of magnitude. Oscillations are discovered in the trailing edge of the specimen photocurrent response; their period is found to be equal to that of self-sustained current oscillations caused by slow recombination waves. Time-dependent profiles of photocurrent response are obtained that are in qualitative and quantitative agreement with ones arrived at in an earlier computer simulation.