On the mechanism for dose rate dependence of stationary luminescence of F and F+ centres excited by electron beam in α-Al2O3

We have examined the kinetic model proposed by Moroٌo and Hodgson for the dose rate dependence of stationary luminescence of colour centres under electron beam excitation. A set of kinetic balance equations based on their model is formulated and analytic solution is derived in terms of stationary concentrations of electrons and holes under irradiation. The solution shows that the ratio of F+ to F luminescence intensities is proportional to the stationary concentration of holes. For high electron beam currents, the effect of saturation of the F centre emission is predicted. Possible mechanisms related to dose rate dependent quenching of the F centre are presented.