Engineering Efficiency Droop in InGaN/GaN Multiple Quantum Well LEDs

In this work, we address the technologically important issue of efficiency droop pronounced in InGaN/GaN multiple quantum well (QW) LEDs. A two-fold modeling approach is employed where: 1) the NEMO 3-D tool is used to compute the atomistic strain fields and associated polarization potentials in the active region, and 2) the outputs from NEMO 3-D are then coupled to the Synopsys TCAD tool to determine the terminal electrical and optical properties of the device. Next, a series of numerical experiments are performed that mainly aims to improve the efficiency droop without compromising the internal quantum efficiency (IQE) of the device. These include:1) varying the QW thickness, 2) employing different configurations of tri-material barriers, 3) varying the molar concentration of the barrier materials, and 4) varying the doping density in the barrier region.