Cathodoluminescence characterization of dislocations in gallium nitride using a transmission electron microscope

Cathodoluminescence technique combined with transmission electron microscopy ~TEM-CL! has
been used to characterize optical properties of dislocations in GaN epilayers. The dislocations act as
nonradiative centers with different recombination rates. TEM-CL observation showed that even for
the same Burgers vector of a, the dislocations show different electrical activity depending on the
direction of dislocation line, i.e., the edge-type dislocation parallel to the c plane is very active,
while the screw-type one is less active. The simulation of the CL images gives us the information
of parameters such as carrier lifetime and diffusion length.