Ultraviolet light emitting diodes

Abstract

The paper presents a review of the recent development of III-nitride based deep UV light emitting diodes (LEDs). Main applications of the deep UV LEDs are introduced. Review of material issues is focused on the lattice mismatch between the substrate and the active layer and at heterojunctions in multiple quantum well structures forming the active layer, the localization of nonequilibrium carriers, the material properties limiting the internal quantum efficiency, and the effect of efficiency droop at high density of nonequilibrium carriers. AlGaN is currently the semiconductor of choice for development of deep UV LEDs, so this material is the most discussed one in this review, though some information on AlInGaN is also provided. Keywords: light emitting diodes, ultraviolet light sources, III-nitride semiconductors, AlGaN