Chapter 7: Power dependent cathodoluminescence in III-Nitrides heterostructures: From internal field screening to controlled band gap modulation

The aim of this chapter is to show mainly the potentiality of the cathodoluminescence (CL) technique and to what extent it can be applied in the study of III-nitrides heterostructures. A quite recent and unusual application of the CL technique, namely powerdependent CL, will be presented, exploiting and discussing the influence of different injection power conditions, from low to high injection regimes (the latter occurring for n >> n0 free carrier concentration, with typical values ranging from about 1016-1020 injected e-h pairs cm-3). It has therefore been decided to abbreviate the basics of the technique, which can be easily found in dedicated textbooks, in favor of a deeper discussion of the experimental examples and of some peculiarities of the technique.