Enhancement of hole injection with Mg-Si-codoped barriers in InGaN-based light-emitting diodes

The advantages of an InGaN light-emitting diode (LED) structure with Mg-Si-codoped barriers are studied numerically in this paper. Energy band diagrams, carrier concentrations in the active region, radiative recombination rates in the quantum wells (QWs), light-current performances, and internal quantum efficiency (IQE) are investigated. Simulation results suggest that by employing the Mg-Si-codoped barriers, the light-output power and IQE are more significantly improved than LEDs with step-Si-doped barriers when compared with the conventional LEDs with wholly Si-doped barriers, due to modified band diagrams, which are favorable for improvement of hole injection efficiency. Moreover, simulation also indicates that the optical performance can be further improved if the Si doping concentration of quantum barriers (QBs) is decreased gradually along the growth direction for the LED with Mg-Si-codoped barriers.