Polarization of edge emission from III-nitride light emitting diodes of emission wavelength from 395 to 455 nm

Abstract

Polarization-resolved edge-emitting electroluminescence of InGaNGaN multiple quantum well (MQW) light emitting diodes (LEDs) from 395 to 455 nm was measured. Polarization ratio decreased from 3.2 of near-ultraviolet LEDs (395 nm) to 1.9 of blue LEDs (455 nm). Based on TE mode dominant emissions in InGaNGaN MQWs, compressive strain in well region favors TE mode, indium induced quantum-dot-like behavior leads to an increased TM component. As wavelength increased, indium enhanced quantum-dot-like behavior became obvious and E∥C electroluminescence signal increased thus lower polarization ratio. Electroluminescence spectrum shifts confirmed that quantum dotlike behaviors rather than strain might be dominant in modifying luminescence mode of InGaNGaN MQWs from near ultraviolet to blue. © 2007 American Institute of Physics.