Performance improvements in InGaN/GaN light-emitting diodes using electron blocking layer with V-shaped graded Al composition

• Characteristics of light emitting diode with graded Al composition EBL.
• EBL with a graded Al composition can enhance hole injection and electron confinement.
• V-shaped EBL has increased barrier height and width owing to the reduced polarization.

In this study, AlGaN electron blocking layers (EBLs) with graded Al compositions have been numerically investigated to improve hole injection and electron confinement in InGaN/GaN-based light-emitting diodes (LEDs). Compared to LEDs with reference structure the output power of the proposed LEDs with decreasing/increasing (V-shaped) grading of the Al composition along the EBL growth direction was increased by a factor of ∼2.5, whereas the efficiency droop at high currents was greatly reduced. In addition, the forward voltage was reduced from 3.69 V to 3.42 V at 20 mA. These results indicate that well-designed EBLs using a V-shaped graded Al composition can enhance hole injection and electron confinement by reducing the polarization effect in these devices.

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