Study of dual-blue light-emitting diodes with asymmetric AlGaN graded barriers

Abstract:

A dual-blue light-emitting diode (LED) with asymmetric AlGaN composition-graded barriers but without an AlGaN electron blocking layer (EBL) is analyzed numerically. Its spectral stability and efficiency droop are improved compared with those of the conventional InGaN/GaN quantum well (QW) dual-blue LEDs based on stacking structure of two In_0.18Ga_0.82N/GaN QWs and two In_0.12Ga_0.88N/GaN QWs on the same sapphire substrate. The improvement can be attributed to the markedly enhanced injection of holes into the dual-blue active regions and effective reduction of leakage current.