Upping the internal quantum efficiency of green light‐emitting diodes by employing a graded AlGaN barrier and an electron blocking layer

Abstract

Abstract Two different device structures are numerically studied, and their optoelectronic characteristics with standard structure are compared. The authors minimized the uneven carrier distribution across the active region. By replacing the first quantum barrier with graded AlGaN and using a graded AlGaN electron blocking layer, in the structure proposed by the authors, the injection of holes into the active region is improved. By using the graded AlGaN barrier, the concentration of injected electrons is also controlled because of the additional barrier height. As a result, the contribution of radiative recombination is boosted. The droop ratio of the proposed structure is reduced to ∼34% at 100 A cm−2 in comparison to other devices.

Keywords

• gallium compounds
• wide band gap semiconductors
• aluminium compounds
• III‐V semiconductors
• light emitting diodes
• optical materials