Table 3 State-of-the-art micro-LED (1–10 μm) performance based on the RIE-free micro-LED fabrication approaches
From: Advanced technologies in InGaN micro-LED fabrication to mitigate the sidewall effect
Direct epitaxy | Method | Wavelength | Pixel size, PPI |
Confined selective epitaxy158 | 520 nm at 30 A cm−2 | 3.6 μm, 4536 | |
Operation voltage | Reverse leakage | EQE peak | |
3.4 V at 60 A cm−2 | 1.3 × 10−2 A cm−2 at −4 V | 6.0% | |
Other characterizations of interest | |||
Luminance peak>107 cd m–2, IQE of 28% | |||
Method | Wavelength | Pixel size, PPI | |
Confined selective epitaxy159 | 642 nm at 10 A cm−2 | 2 μm, 7257 | |
Operation voltage | Reverse leakage | EQE peak | |
~3.1 V at 10 A cm−2 | / | 1.75% | |
Other characterizations of interest | |||
Luminance peak > 3.5 × 107 cd m–2 | |||
Ion implantation | Method | Wavelength | Pixel size, PPI |
F− implantation on n-GaN163 | 460 nm | 10 μm, 1270 | |
Operation voltage | Reverse leakage | EQE peak | |
2.83 V at ~16 A cm−2 | ~3.1 × 10−6 A cm−2 at −5 V | 20.4% | |
Other characterizations of interest | |||
Output power density of 82.1 W cm−2 at 220 A cm−2 31.7% EQE droops from JEQE-peak (~40.8 A cm−2) to 220 A cm−2 | |||
The performance of pixels with other sizes in this work | |||
For 6 µm pixels: 10.1% EQE peak, 8.4% EQE droops from JEQE-peak (~113.3 A cm−2) to 220 A cm−2 | |||
For 8 µm pixels: 15.3% EQE peak, 17.9% EQE droops from JEQE-peak (~63.7 A cm−2) to 220 A cm−2 | |||
Neutral beam etching | Method | Wavelength | Pixel size, PPI |
Cl2-based NBE process174 | 451 nm | 3.5 μm, / | |
Operation voltage | Reverse leakage | EQE peak | |
~3.0 V at 10 A cm−2 | ~1.2×10−4 A cm−2 at −4 V | 37.5% | |
Other characterizations of interest | |||
26% efficiency droop from JEQE-peak (3 A cm−2) to 0.01 A cm−2 | |||
The performance of pixels with other sizes in this work | |||
For 6.5, 10.5, 20.5 μm pixels: EQE > 30% | |||
For 6.5, 10.5, 20.5 μm pixels: 34.7%, 36.7%, 37.2% efficiency droop from JEQE-peak (3 A cm−2) to 0.01 A cm−2 | |||
Metal-assisted chemical etching | Method | Wavelength | Pixel size, PPI |
HCl-based acid chemistry182 | 445 nm | 5 μm, / | |
Operation voltage | Reverse leakage | EQE peak | |
~9.8 V at 0.1 A cm−2 | 1.0×10−4 A cm−2 at −2 V | > 15.0% | |
Plasma insulation | Method | Wavelength | Pixel size, PPI |
H2 plasma treatment185 | /(Green) | 5 μm, 2822 | |
Operation voltage | Reverse leakage | EQE peak | |
~2.5 V at 10 A cm−2 | / | 9.6% | |
Method | Wavelength | Pixel size, PPI | |
H2 plasma treatment184 | 666 nm at 11.5 A cm−2 | 5 μm, 2822 | |
Operation voltage | Reverse leakage | EQE peak | |
3.6 V at 12 A cm−2 | ~1.3 × 10−5 A cm−2 at −4 V | / | |
Other characterizations of interest | |||
936 mW cm−2 at 115 A cm−2 with 632 nm emission | |||
Method | Wavelength | Pixel size, PPI | |
Selective thermal oxidation | |||
Air oxidation186 | 551 nm at 28 A cm−2 | 10 μm, 1270 | |
Operation voltage | Reverse leakage | EQE peak | |
2.9 V at 10 A cm−2 | 1.2 × 10−6 A cm−2 at −10 V | > 6.48% | |
