InGaN monolithic full-color light-emitting diode developed by selective removal of active layers in a single p–n junction

Abstract

We demonstrate a monolithic InGaN light-emitting diode (LED) that emits red, green, and blue (RGB) light. The proposed LED has a simple structure with stacking RGB light-emitting layers on n-GaN, wherein unnecessary layers were removed based on the desired emission color and a stacking p-GaN layer. The electroluminescence characteristics of the LED indicated that the peak wavelengths at 20 mA are R: 632.9 nm, G: 519.0 nm, and B: 449.5 nm, and the external quantum efficiencies are R: 0.28%, G: 8.3%, and B: 0.84%. This structure can be manufactured using only semiconductor processes, thus rendering smaller and higher-resolution microdisplays possible.

InGaN-based blue, green monolithic micro-LED display with n-type interlayer

“…These results would promise a monolithic full-color micro-LED display with the InGaN-based R-, G-, and B-LEDs. Although our proposed manufacturing method has the potential technical problem of reduced luminous efficiency due to etching and regrowth, 32) it has the following advantages. Because the p-contact layer is formed only on the surface, low driving voltages can be achieved using conventional annealing procedures and proven anode electrodes.…”

“…30) We successfully demonstrated full-color monolithic LEDs by selective etching of the R-, Gemitting active layer and regrowth of the p-layer to an LED epitaxial wafer with R-, G-, and B-emitting active layers separated by an n-type interlayer. 31,32) This structure had neither a complex three-dimensional structure nor multiple pn junctions in the stacking direction. R-, G-, and B-LEDs with simple p/n junctions can be easily horizontally integrated using only conventional epitaxial and process techniques, resulting in easy driver control as well as individually prepared LED types.…”

Improving the luminous efficiency of red nanocolumn μ-LEDs by reducing electrode size to ϕ2.2 μm

“…For the monolithic integration of RGB μLEDs, various technologies have been used. [3][4][5][6][7][8][9] GaN nanocolumns are columnar nanocrystals, 10,11) and their ordered nanocolumn arrays have been fabricated via selective area growth (SAG) using RF-plasma-assisted MBE (RF-MBE). [11][12][13][14] The nanocolumn diameter controls the emission color of InGaN/GaN nanocolumn arrays, 11,15) which have been used for the monolithic integration of nanocolumn multi-colored LEDs.…”

Stray light reduction in monolithic GaInN-based μLED arrays for high-definition display realization

“…9) Furthermore, a technique to fabricate RGB LEDs on the same substrate by selective etching and re-growth of p-GaN layers has also been reported. 10) Compared to AlGaInP and GaAs LEDs, GaInN-based LEDs have not shown a considerable drop in efficiency when miniaturized into squares of several micrometers to several tens of micrometers, known as μLEDs. [11][12][13][14] Developing low-resistance GaN-based tunnel junctions (TJs) 15) has made it possible to drive LEDs using only n-electrodes and form low-resistance ohmic contacts 16) even after device processes such as plasma etching.…”