Micro-LEDs have long promised to transform displays for smartphones, televisions, smart glasses and immersive virtual-reality headsets, combining extraordinary brightness with deep contrast and low power consumption. Yet the technology has faced a stubborn problem precisely where its advantages should become greatest: at microscopic dimensions, efficiency can collapse. A study published in Nature Photonics reports a manufacturing technique designed to overcome that barrier, allowing III-nitride micro-LEDs to retain—and in some cases improve—their performance as their dimensions shrink. The researchers describe the method as in situ dry repair and passivation, or IDRP, and report record external quantum efficiencies in 2-micrometre blue and green devices.
Micro-LEDs are inorganic light-emitting diodes made from individually addressable microscopic pixels. In III-nitride devices, including the blue and green LEDs commonly based on indium gallium nitride, light is generated when electrons and holes recombine in a semiconductor region called the active layer. The resulting photons can be produced at very high brightness, while the inorganic material offers strong resistance to aging and image burn-in compared with many conventional display technologies. The smaller the pixel, however, the more difficult it becomes to preserve the electrical and optical properties of the device. This is particularly important for augmented-reality and virtual-reality displays, where extremely high pixel densities require emitters only a few micrometres wide.
The central difficulty arises during the etching process used to define individual pixels. To separate one micro-LED from the next, manufacturers typically use a plasma-based dry etch to carve narrow trenches into the semiconductor wafer. Although effective for producing small structures, the energetic ions and reactive species in the plasma can damage the exposed sidewalls of each device. These damaged surfaces contain crystal defects and electrically active states that can capture charge carriers or provide unwanted paths for current. Instead of recombining radiatively in the active region and producing light, electrons and holes may recombine non-radiatively at the sidewall, converting electrical energy into heat. The result is lower efficiency, increased leakage current and greater sensitivity to device size.
As an LED becomes smaller, its sidewall area becomes more significant relative to its active light-emitting volume. This geometric shift intensifies the influence of surface defects. A defect that has a limited effect in a large LED can dominate the behaviour of a device only a few micrometres across. This size-dependent degradation has been one of the most serious obstacles to commercial micro-LED manufacturing, because shrinking pixels to achieve higher resolution can lead to a disproportionate loss of brightness and efficiency. It can also reduce the number of functioning devices on a wafer and make the pixels more vulnerable to electrical overstress.
The IDRP strategy addresses the problem directly during fabrication by combining dry repair and passivation in an integrated process. Rather than allowing plasma-damaged sidewalls to remain untreated or relying on a separate, more complicated recovery sequence, the method repairs the affected semiconductor surfaces and then passivates them in situ. In semiconductor engineering, passivation means chemically and electrically stabilizing a surface so that defects are less able to trap carriers or conduct unwanted current. Performing the treatment without exposing the device to an additional processing environment is intended to limit contamination, simplify manufacturing and preserve the repaired surface before later process steps.
According to the researchers, this approach substantially suppresses the efficiency loss normally associated with decreasing device dimensions. More strikingly, the study reports a reversed size effect: in the IDRP-treated samples, efficiency increases as the micro-LEDs become smaller rather than declining. The behaviour was observed even for devices measuring just 1.6 micrometres. This result challenges the conventional assumption that smaller III-nitride emitters must inevitably be less efficient because their sidewalls exert greater influence. By controlling the surfaces created during etching, the researchers indicate that the relationship between pixel size and performance can be fundamentally altered.
The reported performance figures highlight the scale of the advance. IDRP-treated 2-micrometre blue InGaN micro-LEDs reached a peak external quantum efficiency of 64.7 percent, while equivalent green devices achieved 55.1 percent. External quantum efficiency measures the number of photons emitted from a device relative to the number of electrons injected into it, making it a key indicator of how effectively electrical current is converted into useful light. The values reported in the study are described as record highs for micro-LEDs of these colours and dimensions. They are especially significant because blue and green emitters are essential components of full-colour displays, while green InGaN devices have historically faced demanding material and efficiency challenges.
The benefits were not limited to optical output. The researchers also report substantially improved manufacturing yield, meaning a larger fraction of fabricated micro-LEDs function correctly. This is crucial for displays containing millions of pixels, since even a small failure rate can produce visible defects or require costly repair and redundancy schemes. IDRP-treated devices also showed stronger electrostatic discharge robustness. Electrostatic discharge can damage microscopic semiconductor structures during handling, assembly or operation, and its effects can become more severe as device dimensions shrink. Improving resistance to such events could make micro-LED production more reliable beyond the laboratory.
The study further suggests that IDRP is not restricted to one colour or one narrow class of device. The researchers describe the method as broadly effective across the III-nitride material system, raising the possibility that it could be applied to different wavelengths and micro-LED architectures. Because the process is dry and integrated with semiconductor-standard manufacturing, it may avoid some of the throughput, contamination and compatibility issues associated with wet chemical treatments or complex post-etch recovery methods. A process that can be incorporated into existing wafer fabrication could be especially valuable for scaling displays from experimental arrays to large production volumes.
The researchers demonstrated the technology in a nitride microdisplay aimed at emerging augmented-reality and virtual-reality applications. For these systems, displays must combine high pixel density, strong brightness, low power consumption and dependable operation in a compact form factor. Micro-LEDs are attractive because their inorganic emitters can support high luminance, but their commercial progress has been slowed by the difficulty of producing uniformly efficient pixels at scale. By reducing sidewall-related losses while improving yield and electrical robustness, IDRP could address several of these problems at once. The reported results do not remove every challenge facing micro-LED manufacturing, including mass transfer, driver integration, colour conversion and full-panel uniformity, but they target one of the fundamental semiconductor limitations.
The significance of the work extends beyond a single performance record. If efficiency can remain independent of—or even improve with—shrinking pixel dimensions, manufacturers may gain greater freedom to design higher-resolution displays without paying the traditional optical penalty. That could accelerate the development of lightweight near-eye displays, high-brightness wearable screens and other applications requiring microscopic pixels. The combination of a 64.7 percent peak external quantum efficiency in blue devices, 55.1 percent in green devices, operation at micrometre-scale dimensions and improved production resilience makes IDRP one of the more notable process advances reported for III-nitride micro-LEDs. The researchers’ findings suggest that repairing the damage caused by making tiny pixels may be as important as inventing new emitter materials—and could help move micro-LEDs closer to industrial-scale display manufacturing.
Subject of Research: III-nitride micro-LED efficiency, plasma-induced sidewall damage, dry repair and passivation, and advanced microdisplay manufacturing
Article Title: In situ dry repair and passivation unlocks size-independent performance in Ⅲ-nitride micro-LEDs
Article References: Yan, J., Li, J., Li, G. et al. In situ dry repair and passivation unlocks size-independent performance in Ⅲ-nitride micro-LEDs. Nature Photonics (2026). https://doi.org/10.1038/s41566-026-01990-4
Image Credits: AI Generated
DOI: https://doi.org/10.1038/s41566-026-01990-4
Keywords: micro-LEDs, III-nitride semiconductors, InGaN, blue micro-LEDs, green micro-LEDs, sidewall damage, plasma etching, passivation, external quantum efficiency, augmented reality, virtual reality, microdisplays, semiconductor manufacturing
Tags: applications in augmented reality and virtual realitychallenges in microscopic pixel efficiencydeep contrast and low power consumption in micro-LEDsIII-nitride micro-LED performancein situ dry repair and passivationinorganic light-emitting diodesmicro-LED display technologymicro-LED manufacturing techniquesovercoming efficiency collapse in micro-scale LEDspassivation methods for nanoscale LEDsrecord quantum efficiency in micro-LEDssize-independent efficiency in micro-LEDs
