Enhanced light extraction in 260 nm light-emitting diode with a highly transparent p-AlGaN layer

AlGaN LEDs have been studied as efficient light sources in DUV. One of the central issues in DUV LEDs is their low light extraction efficiency owing to the absorption in a p-contacting layer and a metal electrode. We report the fabrication of a 260 nm LED containing a transparent p-AlGaN layer. The LED showed a relatively good current injection with an increase in forward voltage compared with a p-GaN LED. Its efficiency reached 2%, almost equivalent to that of the p-GaN LED. In addition, a nearly zero absorption in the p-contacting layer increased the light extraction efficiency by using a reflective metal electrode.