ABSTRACT
This chapter describes a GaN layers grown by metal-organic chemical vapour deposition on sapphire substrates. It explains a scanning electron microscope /electron beam induced current (EBIC) study of individual dislocations in GaN epilayers. The EBIC contrast profiles have been measured and compared with simulated ones. Profile fitting has allowed the evaluation of the dislocation recombination strength and the minority carrier diffusion length in dislocation-free regions. The chapter explores the dependence of dislocation EBIC contrast on temperature and electron beam current. The common way to obtain information about the dislocation charge and dislocation energy levels from the EBIC measurements is to study the contrast dependence on temperature and excitation level. The recombination strength plays a role similar to that of surface recombination velocity for two-dimensional defects and can be considered as an important parameter describing quantitatively the dislocation effect on the excess carrier distribution and recombination rate.
