Spatially Resolved Cathodoluminescence in the Vicinity of Defects in the High-Efficiency InGaNGaN Blue Light Emitting Diodes

Abstract EN

In addition to the standard 447 nm blue emission from the InGaN/GaN multiple quantum wells, a high-energy shoulder is clearly observed in cathodoluminescence spectra of the high-efficiency InGaN/GaN blue light emitting diodes grown on sapphire substrates by metalorganic chemical vapor deposition.

Monochromatic cathodoluminescence images of the samples measured at low temperature reveal a competition between the two emissions in the vicinity of the dislocations.

The high-energy emission is dominant at the regions near the dislocation cores, while the blue emission is enhanced around the dislocation edges.

The high-energy emission region is considered as a potential barrier that prevents the carriers for the blue emission from nonradiatively recombining at the dislocations.