Photoconductivity and negatively correlated defects

The effects of negatively correlated defects on the transient photoconductivity are analyzed using a first-order kinetic approach. The predicted behavior explains the Staebler-Wronski effect observed in $a-\mathrm{S}\mathrm{i}$:$\mathrm{H}$ without the assumption of optically induced changes in the defect density. In addition, the analysis predicts a maximum in the photoresponse to a light step and an anomalous dependence of photocurrent on chopping frequency, both of which have recently been observed in chalcogenide glasses.