抄録
High-efficiency ultraviolet (UV) light sources, i.e., UV light-emitting diodes (LEDs) or laser diodes (LDs), are very attractive for application to white lighting, high-density memories, medical fields, etc. We have demonstrated that 300-350 nm UV emission is considerably enhanced by the introduction of several percent of In into AlGaN due to an In-segregation effect. We fabricated InAlGaN-based deep UV LEDs on sapphire substrate that had an emission wavelength at 308-314 nm, and we obtained sub-milliwatt output power under pulsed operation. We also fabricated InAlGaN-based quantum-well (QW) LEDs on GaN substrates in order to eliminate the effects of threading dislocations. We achieved a remarkable increase in output power by using a GaN substrate instead of sapphire substrates. As a result, the maximum UV output power obtained was as high as 3.8 mW at 351nm and 6.3 mW at 358 nm under room temperature (RT) CW operation.
