DEEP ULTRAVIOLET LIGHT EMITTING DIODES USING AlGaN QUANTUM WELL ACTIVE REGION

摘要

We report our recent work aimed at developing deep UV III-N LEDs with emission wavelengths λ≤340 nm over sapphire substrates. Our device design is based on using high Al-content AlGaN multiple quantum wells active region. Novel pulsed atomic layer epitaxy (PALE) approach is used to deposit short period AlN/AlGaN superlattice for the buffer and thick n~+-AlGaN layers for the n-contacts, which tailors strain and reduces the number of threading dislocations. The p-contact region comprises of the p-AlGaN-GaN heterojunction that aids hole accumulation and thus allows for the devices to operate even at temperatures as low as 10-100K. The linewidths of the spectral emissions were about 10 nm. Room temperature powers for flip-chipped devices were then measured using an integrating sphere. Output powers of 1 mW (100 mA dc) and 10 mW (1 A pulsed) at 325 nm and of 0.47 mW (260 mA dc) and 3 mW (1 A pulsed) at 278 nm were achieved.