Materials and device developments for ultraviolet LEDs and laser diodes

AlGaInN-based ultraviolet (UV) light emitters have recently become the focus of intense research since semiconductor UV optical sources offer the potential of low cost, small size, low power, and high reliability. In this paper, we summarize critical elements for optimizing LED and LD performance in the sub-390 nm range. Lifetime results on both LEDs and LDs are discussed along with issues concerning further increasing the lifetime of these short wavelength devices, increasing their efficiency, and pushing emission wavelength even shorter.