Polarized spontaneous emission from blue-green m-plane GaN-based light emitting diodes

The polarization of spontaneous emission was investigated for various indium compositions and quantum wells on m-plane oriented gallium nitride (GaN) light emitting diodes (LEDs) grown on bulk-GaN substrates. Internal light scattering and depolarization was mitigated with application of absorber materials to the LED die. The polarization ratio (ρ) was measured under electrical injection for devices with InGaN active regions emitting up to 520 nm and observed as high as 96%. Values of ρ were independent of drive current. The valence band energy separation (ΔE) was characterized using spectral measurement and temperature dependent optical analysis of valence band hole distributions.