Suppression of the subband parasitic peak by 1 nm i-AlN interlayer in AlGaN deep ultraviolet light-emitting diodes

The origin and suppression of the subband parasitic peak in AlGaN deep ultraviolet light-emitting diodes have been studied. The parasitic peak is clarified to come from a p-AlGaN cladding layer and to be related to Mg dopants. By using 1 nm i-AlN as an interlayer between the active region and the p-AlGaN cladding layer, this peak is suppressed efficiently. The devices with such an interlayer show improved output power by a factor of 4 at injection current density of 20 A/cm(2), except that the series resistance and turn-on voltage are slightly increased. (C) 2008 American Institute of Physics.