The future of ZnO light emitters

Compact, solid-state UV emitters have many potential applications, and ZnO-based materials are ideal for the wavelength range 390 nm and lower. However, the most efficient solid-state emitters are p-n junctions, and p-type ZnO is difficult to make. Thus, the future of ZnO light emitters depends on either producing low-resistivity p-type ZnO, or in mating n-type ZnO with a p-type hole injector. Perhaps the best device so far involves an n-ZnO/p-AlGaN/n-SiC structure, which produces intense 390 ± 1 nm emission at both 300 K and 500 K. However, development of p-ZnO is proceeding at a rapid pace, and a p-n homojunction should be available soon.