Development of AlGaN-based deep-UV LEDs using high-quality AlN on sapphire

AlGaN and quaternary InAlGaN alloys are attracting much attention as candidate material for realizing deep-ultraviolet (DUV) light-emitting diodes (LEDs) or laser diodes (LDs) [1,2]. We demonstrated 222-351 nm DUV LEDs with AlGaN and InAlGaN quantum wells (QWs) fabricated on low threading dislocation density (TDD) A1N buffer on sapphire [1-6].