Realization of 340 nm-band high-power InAIGaN-based ultraviolet light-emitting diodes by the suppression of electron overflow

摘要

(In)AlGaN alloys are attracting much attention as candidate materials for realizing deep ultraviolet (UV) light-emitting diodes (LEDs). In this study, we demonstrated high-power CW operations of 340 nm-band InAIGaN-based UV-LEDs by suppressing electron overflow using optimized electron injec-tion structures. LED layer structure consisting of quaternary InAIGaN quantum wells (QWs), Mg-doped InAIGaN elec-tron blocking layer (EBL) and Mg-doped InAIGaN p-type layers was grown on sapphire/AIN/AIGaN template by low-pressure metal-organic chemical-vapor deposition (LP- MOCVD). The output power was dramatically improved by increasing the potential barrier height of EBL. Furthermore, the output power was improved by increasing the depth of the quantum well. These tendencies agree well with the theoretical analysis calculated by a device simulator. The maximum output power was 8.4 mW under room temperature (RT) CW operation with peak emission wavelength at 346 nm. These results indicate that the suppression of electron overflow is quite important for the realization of high-efficiency (In)AlGaN-based UV-LEDs.