Influence of Mg-doped barriers on semipolar (20(2)over-bar1) multiple-quantum-well green light-emitting diodes

We report the effects of Mg doping in the barriers of semipolar (20 (2) over bar1) multiple-quantum-well light-emitting diodes (LEDs) with long emission wavelengths (>500 nm). With moderate Mg doping concentrations (3 x 10(18)-5 x 10(18) cm(-3)) in the barriers, the output power was enhanced compared to those with undoped barriers, which suggests that hole transport in the active region is a limiting factor for device performance. Improved hole injection due to Mg doping in the barriers is demonstrated by dichromatic LED experiments and band diagram simulations. With Mg-doped AlGaN barriers, double-quantum-well LEDs with orange to red emission (lambda>600 nm) were also demonstrated. (C) 2011 American Institute of Physics. [doi:10.1063/1.3647560]