Investigations of recombination mechanisms in the pulsed far infra red photoresponse of n-InP

Abstract

Narrow (10–50 ns) far infra red pulses ( λ = 91 μm) with sharp (≤ 1 ns) cut-off are used to probe the recombination dynamics of electrons in high purity n-InP. The decay of the photosignal is investigated for a variety of laser intensities, sample bias voltages, temperatures and compensation ratios. A simple model is outlined to explain the observed linear dependence at low bias of the inverse decay time parameter, τ −1, on electric field. For higher impurity samples at higher intensities the decay exhibits an initial fast component. A more complete model, invoking Auger recombination, is outlined to explain this effect.