Improving GaN-based LEDs with V-defect Engineering

V-defects are pyramid-shaped defects that commonly appear in GaN-based light-emitting diode (LED) structures. They have been shown to increase the efficiency of long-wavelength LEDs by allowing carriers to be laterally injected into c-plane quantum wells, avoiding the effects of the high polarization fields in c-plane III-nitride LEDs that contribute to a high forward voltage bias. The effect of changing the carrier gas flow from hydrogen gas to nitrogen gas during the metalorganic chemical vapor deposition (MOCVD) growth of the quantum barriers within the light-emitting region of the LED was studied, with funding from SSLEEC. Analyses of composition, strain, and thickness of the quantum wells and barriers were performed with X-ray diffraction. Changing the carrier gas was found to increase the density of V-defects as observed by scanning electron microscopy, and the forward voltage of fabricated III-nitride LED devices was shown to decrease.