Current injection emission at 333 nm from Al0.03Ga0.97N/Al0.25Ga0.75N multi quantum well ultraviolet light emitting diodes

Abstract

We demonstrate ultraviolet Al0.03Ga0.97N/Al0.25Ga0.75N multi-quantum-well (MQW) light emitting diodes (LEDs). The room-temperature electroluminescence (EL) emission was peaked at 333.0 nm under pulsed current injection. To our knowledge, this is the shortest wavelength yet reported for nitride QW LEDs. As p-type layers, Mg-doped GaN/AlGaN superlattice (SL) structures were used in order to improve vertical hole conductivity. We obtained a reasonable well width dependence on EL peak wavelength of Al0.01Ga0.99N MQW LEDs, which confirms that the origin of the main emission peak is from the QW regions. The output intensity did not saturate up to current densities approaching 0.33 kA/cm(2). From these results, we found that the SL hole conductive layers are significantly effective for applying to light emitting devices.