On the stability of transient photoconductivity on approaching equilibrium

Stability of photoconductivity of solids when approaching equilibrium is sh own to be effective under illumination and in the dark as well. As the mode ls always lead to nonlinear differential equations, the problem of stabilit y deserved being examined. This was made a few years ago by Joshi, who conc luded positively in favour of an intrinsic instability of equations. It is shown here that this is a misleading conclusion. This is established in the framework of a one-level model, akin to Joshi's model, but we verified tha t our conclusions remain for multi-level models including continuous distri butions.