ABSTRACT
The influence of various threading defects on the luminescence of GaN heterostructures is examined. A combination of transmission electron microscopy and cathodoluminescence in the scanning electron microscope is used to show that threading edge dislocations, as well as pitted regions associated with inversion domains or screw/mixed dislocations act as non-radiative recombination centers in the quantum well (QW) emission from an InGaN/GaN sample. Observations of a decrease in the QW emission wavelength, together with an increase in the carrier diffusion distance, as the electron irradiation dose increases, are illustrated and discussed. Electron holography studies of internal piezoelectric fields in InGaN/GaN structures are briefly reviewed. Recent holography studies showing that threading edge dislocations are highly charged are also presented.
