Effect of Back Diffusion of Mg Dopants on Optoelectronic Properties of InGaN-Based Green Light-Emitting Diodes

The effect of back-diffusion of Mg dopants on optoelectronic characteristics of InGaN-based green light-emitting diodes (LEDs) is investigated. The LEDs with less Mg back-diffusion show blue shifts of longer wavelengths and larger wavelengths with the increasing current, which results from the Mg-dopant-related polarization screening. The LEDs show enhanced efficiency with the decreasing Mg back-diffusion in the lower current region. Light outputs follow the power law L\propto I^m, with smaller parameter m in the LEDs with less Mg back-diffusion, indicating a lower density of trap states. The trap-assisted tunneling current is also suppressed by reducing Mg-defect-related nonradiative centers in the active region. Furthermore, the forward current–voltage characteristics are improved.