Polarization-doped AlGaN light-emitting diode

The development and application of nitride-based light-emitting diodes is handicapped by the low hole conductivity of Mg-doped layers. Mg-doping becomes increasingly difficult with shorter LED wavelength and higher Al-content of the p-AlGaN layers. As an alternative, polarization-induced hole doping in N-face graded AlGaN was recently demonstrated. Using advanced numerical device simulation, we show that the internal quantum efficiency can be strongly increased and the efficiency droop eliminated by using such graded AlGaN layer instead of the traditional AlGaN electron-blocker layer (EBL).