Induced nanosecond absorption in InP:Fe

Induced absorption was observed in an InP:Fe crystal under nanosecond pulse illumination at 1.06- mu m wavelength. The maximum induced absorption was 0.05 cm/sup -1/ when probed at a 1.06- mu m wavelength and 0.30 cm/sup -1/ when probed at a 1.30- mu m wavelength. The kinetics are studied together with the photocurrent giving the recombination times of holes (100 ns) at room temperature and an estimate for that of electrons (0.5 ns). The induced absorption is attributed to a population redistribution of the different iron impurity states. Computer simulations are able to explain all the features found in the experiments and give values for the photoionization cross sections, in particular for the unknown cross section Fe/sup 2+*/ to Fe/sup 3+/+e/sup -/.<
>