Cathodoluminescence microscopy

Abstract

Being as they are the source of light quanta in optoelectronic devices like semiconductor lasers and light-emitting diodes, radiation recombination processes are of great importance in the constituent semiconducting structures. These latter consist of small-thickness epitaxial layers, and their radiative recombination efficiency depends on structural imperfections such as dislocations, usually acting as nonradiative recombination centres, and point defects. Since point defects usually have a nonuniform layer distribution, radiation characteristics are distibuted inhomogeneously over the layers and small-scale structural elements. For such structures, therefore, cathodoluminescence scanning microscopy, determining the microlevel distribution of radiation characteristcics, is an implacable research tool. The effective use of this techniques requires a correct understanding of the radiation-producing processes occurring during the electron probe-semiconductor interaction. A knowledge of the potential and the information capacity of the method is essential.