Piezo-phototronic enhanced dual-wavelength InGaN/GaN multiple quantum wells Micro-LED arrays

Abstract

As a promising technology for next-generation displays due to their high brightness and low power consumption, InGaN-based micro light-emitting diodes (Micro-LEDs) have attracted great attention in recent years. In this work, we detailedly investigate the carrier recombination and transportation process in dual-wavelength InGaN/GaN multiple quantum wells (MQWs) Micro-LED arrays under piezo-phototronic effects using electroluminescence (EL) and time-resolution photoluminescence measurements. With the increase of external strain, the violet EL intensity of dual-wavelength Micro-LED arrays first increases obtaining a maximum enhancement of ∼12% and then decreases, whereas blue EL emission almost maintains constant. Additionally, as the size of Micro-LED decreases, the enhancement obtained via piezo-phototronic effect will reduce, which is attributed to their inherently weaker piezoelectric polarization effect. Combining with dynamic analysis of carriers in the blue quantum well (QW), it is concluded that strain-induced interface polarized charges promote the wave function overlap of electron–hole pair, but reduce the injection of hole carriers in blue QW. Superposition of the above two factors enables the blue EL intensity stable under piezoelectric coupling. These results present a promising potential of piezo-phototronic effects to improve the Micro-LEDs devices.