Constructive studies on the advantages of using Ga- and N-face polarities in conventional and staggered InGaN/GaN QW LEDs

Abstract

In the InGaN/GaN Quantum Well (QW) Light-Emitting Diodes (LEDs), the electron-hole overlap function decreases significantly, and the carrier overflow is exhibited, under certain conditions, which deteriorates the performance of the devices. This hurdle is created by the detrimental effect of the polarization fields. The paper has elaborately presented the comprehensive and constructive studies on the effect of Ga and N-face polarities of GaN, in the conventional and staggered InGaN/GaN QW LEDs. The transition energies, the transition probabilities, the carrier concentrations, and the energy bands of the QW LEDs, are numerically calculated using the self-consistence solutions of the Schrödinger and Poisson equations. The Ga-face QW LEDs have shown a better electron-hole overlap function, even at low operating current. The N-face structures have suppressed the carrier overflow mechanism. A large carrier density has been found in the N-face QWs, due to the change of band structure along the direction of the polarization fields. This information may help the optoelectronic designer to design an efficient device.