Micro‐Light Emitting Diode: From Chips to Applications

Abstract

Typical light‐emitting diodes (LEDs) have a form factor >(300 × 300) µm2. Such LEDs are commercially mature in illumination and ultralarge displays. However, recent LED research includes shrinking individual LED sizes from side lengths >300 µm to values <100 µm, leading to devices called micro‐LEDs. Their advent creates a number of exciting new application spaces. Here, a review of the principles and applications of micro‐LED technology is presented. In particular, the implications of reduced LED size in necessitating mitigation strategies for nonradiative device edge damage as well as the potential for higher drive current densities are discussed. The opportunities to integrate micro‐LEDs with electronics, and into large‐scale arrays, allow pixel addressable scalable integrated displays, while the small micro‐LED size is ideal for high‐speed modulation for visible light communication, and for integration into biological systems as part of optogenetic therapies.

Analysis of Size-Dependent Quantum Efficiency in AlGaInP Micro–Light-Emitting Diodes With Consideration for Current Leakage

“…Compared with another study [27] in which nmax was expressed as 𝐴/𝐶, our expression in ( 9) is more complex because of the effect of the leakage current. Three scenarios for (A) 2 (10) Among these three conditions, nmax becomes proportional to 𝐴 (𝐶 + 𝛽𝐵) ⁄ in two conditions; this is similar to the no-leak case but with a modified leakage term. The value of the maximum carrier concentration approximates 1/(2) in the case of (A) 2 >> A(C + B).…”

“…Micro-LED-based monitors require perfect performance of numerous tasks. Thus, several aspects, such as microassembly, mass transfer, epitaxial growth, and electronic circuitry, must be substantially improved [1,2]. A full-color micro-LED display requires red, green, and blue subpixels on the same backplane and various active materials to generate these colors: InGaN for blue and green and AlGaInP or high-In content InGaN for red [3][4][5][6][7][8].…”

Augmented reality and virtual reality displays: emerging technologies and future perspectives

“…The high peak brightness, fast response time, true dark state, and long lifetime of micro-LEDs are attractive for display applications. Therefore, many companies have since released their micro-LED prototypes or products, ranging from largesize TVs to small-size microdisplays for AR/VR applications 53,54 . Here, we focus on micro-LEDs for near-eye display applications.…”

Ultrasmall and ultradense InGaN-based RGB monochromatic micro-light-emitting diode arrays by pixilation of conductive p-GaN

“…Owing to their high efficiency, brightness, and stability, InGaN-based micro-light-emitting diodes (μLEDs) have been considered as core devices in next-generation displays for a wide variety of applications, e.g., wall displays/televisions, smartphones/watches, head-up displays, pico-projectors, and augmented-reality (AR) glasses [1][2][3]. The full-color μLED displays require integration of red, green, and blue (RGB) μLEDs (R: AlGaInP; G and B: InGaN) on the same panel by pick-and-place technologies.…”