Efficient carrier‐injection and electron‐confinement in UV‐B light‐emitting diodes

The effects of the aluminum content x and the magnesium doping concentration in the AlGaN:Mg electron blocking layer on the emission characteristics of ultraviolet light-emitting diodes has been investigated. The carrier injection in the light-emitting diodes is simulated and compared with electroluminescence measurements. The light output power depends strongly on the aluminum mole fraction x as well as on the magnesium supply in the vapor phase during the growth of the AlGaN:Mg electron blocking layer. The highest output power has been found for an aluminum content x of around 44% and an Mg/III-ratio of 3.0% for light-emitting diodes with an emission wavelength near 320 nm. This effect can be attributed to an improved carrier injection and confinement preventing electron leakage into the p-doped layers of the light-emitting diode and an effective hole injection into the active region.