The influence of Al composition on point defect incorporation in AlGaN.

The effects of point defects in AlxGa1-xN (x = 0-0.33) films with similar threading dislocation densities were investigated. The epitaxial layers were grown under conditions applicable to laser-diode quantum wells, barriers and waveguide layers. The evolution of deep level defect energy and density were quantitatively tracked versus x using deep level optical spectroscopy. Three defect levels were observed, whose defect density increased with x. The energy level of a defect suspected to be related to the group-III vacancy appeared to track the vacuum level, and a near-valence band defect level deepened with respect to the valence band maximum. [ABSTRACT FROM AUTHOR]