Barrier effects on the optoelectronic properties of GaN-based irregular multiple quantum wells for dichromatic white LEDs

The GaN-based irregular multiple quantum well (IMQW) structures for dichromatic white light-emitting diodes (LEDs) are assembled by two different types of QWs emitting complementary blue and yellow light. The electronic and optical properties of the designed GaN-based IMQW structures are investigated in details by fully considering the effects of strain, well-coupling, valence band-mixing and polarization effect by employing a newly modified theoretical model based on the k·p theory. The influences of the height and thickness of the barrier between blue QWs and yellow QWs together with the polarization effect on the optoelectronic properties of GaN-based IMQW structure are analyzed. Numerical results show that the ratio of the two color lights emmited from the IMQW structure for dichromatic white LED can be tuned by changing the height and thickness of the barrier between two types of QWs.