Monolithic integration of AlGaInP-based red and InGaN-based green LEDs via adhesive bonding for multicolor emission

Abstract

In general, to realize full color, inorganic light-emitting diodes (LEDs) are diced from respective red-green-blue (RGB) wafers consisting of inorganic crystalline semiconductors. Although this conventional method can realize full color, it is limited when applied to microdisplays requiring high resolution. Designing a structure emitting various colors by integrating both AlGaInP-based and InGaN-based LEDs onto one substrate could be a solution to achieve full color with high resolution. Herein, we introduce adhesive bonding and a chemical wet etching process to monolithically integrate two materials with different bandgap energies for green and red light emission. We successfully transferred AlGaInP-based red LED film onto InGaN-based green LEDs without any cracks or void areas and then separated the green and red subpixel LEDs in a lateral direction; the dual color LEDs integrated by the bonding technique were tunable from the green to red color regions (530–630 nm) as intended. In addition, we studied vertically stacked subpixel LEDs by deeply analyzing their light absorption and the interaction between the top and bottom pixels to achieve ultra-high resolution.

Micro-light-emitting diodes with quantum dots in display technology

“…Alignment and assembly are important factors for the integration of these two separate parts. Various integration technologies have been investigated, including metal wiring 78,79 , flip chip bonding 80 , microtube bonding 81 and adhesive bonding 82,83 (Fig. 7).…”

Analysis of InGaN-Delta-InN Quantum Wells on InGaN Substrates for Red Light Emitting Diodes and Lasers

“…While blue LEDs have been very well optimized over the past decade, often boasting external quantum efficiencies (EQE) greater than 85%, InGaN LEDs and lasers emitting at longer wavelengths still struggle to match the efficiencies of their blue counterparts, making it difficult to fabricate highefficiency, high-brightness red emitters for lighting, display, and laser applications [4][5][6][7][8][9]. Consequently, µLED displays often rely on AlInGaP for red-emitting pixels, which complicates the fabrication process and increases manufacturing costs [10]. Red lasers using InGaN QWs as the gain medium have not yet been achieved, and as a consequence InGaN quantum dot lasers are instead used in applications which require compact, high-efficiency RGB laser diodes, such as DMD laser projectors [11][12].…”

Monolithic full‐color microdisplay using patterned quantum dot photoresist on dual‐wavelength LED epilayers

“…Monolithic fabrication, with RGB subpixels directly fabricated at the wafer level on the same display panel, is thus preferred for high resolution microdisplays. Several monolithic approaches, including works using molecular beam epitaxy (MBE) growth of InGaN nanowires, 6,7 strain‐induced wavelength shift, 8–10 wafer stacking, 11,12 and epi‐layer adhesive bonding, 13,14 have been discussed. However, simple and reliable methods have yet to be demonstrated for high yield production of full‐color LED microdisplays to date.…”