Improving Performance of Algan-Based Deep-Ultraviolet Light-Emitting Diodes by Inserting a Higher Al-Content Algan Layer Within the Multiple Quantum Wells

Characteristics of AlGaN-based deep-ultraviolet light-emitting diodes (DUV-LEDs) with light-emitting wavelength around 265 nm are investigated by inserting a higher Al-content AlGaN layer within the multiple quantum wells (MQWs). It is found that there is a significant enhancement of light output power (LOP) and efficiency droop for DUV-LEDs with the inserted higher Al-content AlGaN layer compared to those with the conventional one. The location of the AlGaN layer with higher Al-content in the MQWs is proven to greatly affect the distribution of carriers and the overlap of electron and hole wave functions. The optimal structure can be achieved when the higher Al-content layer is placed on the right side within the MQWs. The key factors for the performance improvements for this specific design is the enhanced hole transport and reduced electron leakage.