Efficient Carrier Confinement in Deep-Ultraviolet Light-Emitting Diodes with Composition-Graded Configuration

Characteristics of deep-ultraviolet (DUV) light-emitting diodes (LEDs) are investigated. DUV LEDs possess severe electron current leakage due to insufficient carrier confinement of the active region. Simply increasing the Al composition of quantum barriers (QBs) or electron-blocking layer (EBL) to enlarge the relevant potential barrier height would arise unexpected detrimental effects, such as extra polarization effect or more obstruction for hole injection. In this paper, band-engineered composition-graded QBs and EBL are proposed to resolve this issue. Simulation results show that, with appropriate designs, the leakage current of DUV LEDs could be effectively diminished with just slight side effects.