Theory of cathodoluminescence contrast from localized defects in semiconductors

An analytical solution is given for the contrast from an individual pointlike defect in the cathodoluminescence mode of a scanning electron microscope. This solution takes into account the influence of recombination at the surface and the internal optical absorption. The cathodoluminescence contrast is shown to differ from the electron-beam-induced current contrast. The pointlike defect is then treated as an elementary segment of an extended defect. Computational results are given for dislocations at various angles to the surface. Some advantages of a simultaneous cathodoluminescence and electron-beam-induced current experiment are pointed out.