Dynamics of capture from free-carrier tails in depletion regions and its consequences in junction experiments

Exponentially decaying tails of free carriers extend from the neutral material into the depletion region of p-n junctions or Schottky barriers. In nonequilibrium, deep level impurities in the depletion region may readily capture free carriers from these tails. The strongly nonexponential time dependence of the capture is calculated here and is compared with experimental data. This nonexponential time dependence is particularly important in deep level transient spectroscopy, and it also appears in many other junction measurements with deep level impurities.