Development and Isolation of Dot LEDs for Display Applications through Electrochemical Etching and Sonochemical Separation

This paper presents a top-down fabrication and an isolation process for producing billions of multifunctional dot light-emitting diodes (LEDs) without a sacrificial layer. The process involves a combination of electrochemical etching (ECE) of an n-GaN layer and sonochemical separation of an etched porous layer to isolate the dot LEDs. The structure of the developed dot LEDs can be expressed as Au/indium tin oxide (ITO)/p-GaN/multiple quantum well (MQW)-InGaN/n-GaN@SiO2. The nanopore size, separation ratio, and emission characteristics of dot LEDs produced by ECE are investigated, as well as the solvent type on ultrasonic separation in the sonochemical process. Blue electroluminance devices fabricated in a vertical structure using dot LEDs exhibit a peak external quantum efficiency (EQE) of 6.21% at an applied voltage of 4.0 V, and a luminous efficacy of 1070 cd m-2, at an applied voltage of 10.0 V. Although the current technology for blue dot LEDs may not produce a higher EQE than the existing display technologies, it is essential to consider that the development of dot LED displays is still in its early stages. Furthermore, the findings show that the dot LEDs have the potential to significantly reduce material costs and provide new opportunities for nanoscale GaN-based LED displays. In this study, nanoscale GaN-based dot light-emitting diodes (LEDs) are successfully developed without using a sacrificial layer by optimizing sequential etching, electrochemical etching, and sonochemical separation processes to replace micro-LED displays. A blue electroluminance device with a vertical structure is fabricated using separate dot LEDs, showing a maximum external quantum efficiency of 6.21% and luminous efficacy of 1070 cd m-2.image