Impact of nanopores in porous GaN on LED emission based on FDTD simulations

We simulated the light extraction efficiency (LEE) of porous GaN-based InGaN/GaN micrometer-sized light-emitting diodes (μLEDs) emitting within the visible wavelength range using the finite-difference time-domain (FDTD) method. The simulations show that the embedding of a porous GaN layer with 40 % porosity reduces the bottom LEE, while the top side LEE of the μLEDs is increased. In addition, it also exhibits complex scattering properties that affect the microcavity structure of these devices. The LEE and the degree of microcavity structure disruption are related to nanopore size and location. This association weakens with increasing wavelength. Also, a decrease in nanopore size corresponds to a diminished impact on μLED optical properties. Since the porous GaN layer contributes to the deposition of high-quality InGaN, controlling pore size of the porous GaN layer will aid the development of GaN-based red μLEDs and full-color displays.