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Process flow for the fabrication of a full-color RGB pixel array. (a) μ-LED array process. (b) Black PR matrices and p-electrode metal lines. (c) Red, green, and blue (transparent) pixel lithography process. (d) Color pixel bonding.
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Red-green-blue (RGB) full-color micro light-emitting diodes (μ-LEDs) fabricated from semipolar (20-21) wafers, with a quantum-dot photoresist color-conversion layer, were demonstrated. The semipolar (20-21) InGaN/GaN μ-LEDs were fabricated on large (4 in.) patterned sapphire substrates by orientation-controlled epitaxy. The semipolar μ-LEDs showed...
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... the via-hole process, followed by ICP-RIE, was used to complete the μ-LED array. Figure 1 schematically illustrates the lithographic process of black PR matrices and QDPR on the semipolar μ-LED array. A black photoresist was used to flatten the μ-LED array and prevent the lateral leakage of blue light. ...
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... μ-LED array. Figure 1 schematically illustrates the lithographic process of black PR matrices and QDPR on the semipolar μ-LED array. A black photoresist was used to flatten the μ-LED array and prevent the lateral leakage of blue light. Then, the Ni/Au (p-electrode metal) lines were deposited on the flattened surface to link each chip, as shown in Fig. 1(b). Next, the gray photoresist, red QDPR, green QDPR, and transparent PR were fabricated by the lithography process sequentially to form a color pixel on a highly-transparent glass substrate with 0.7 mm thickness, as shown in Fig. 1(c). The color pixel size is designed at 80 μm × 80 μm with 30 μm spacing between each pixel. Finally, in ...
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... Then, the Ni/Au (p-electrode metal) lines were deposited on the flattened surface to link each chip, as shown in Fig. 1(b). Next, the gray photoresist, red QDPR, green QDPR, and transparent PR were fabricated by the lithography process sequentially to form a color pixel on a highly-transparent glass substrate with 0.7 mm thickness, as shown in Fig. 1(c). The color pixel size is designed at 80 μm × 80 μm with 30 μm spacing between each pixel. Finally, in Fig. 1(d), the color pixel array on glass was stuck together with μ-LED array by using an aligner and UV ...
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... in Fig. 1(b). Next, the gray photoresist, red QDPR, green QDPR, and transparent PR were fabricated by the lithography process sequentially to form a color pixel on a highly-transparent glass substrate with 0.7 mm thickness, as shown in Fig. 1(c). The color pixel size is designed at 80 μm × 80 μm with 30 μm spacing between each pixel. Finally, in Fig. 1(d), the color pixel array on glass was stuck together with μ-LED array by using an aligner and UV ...
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... 123 To address this polarization issue for MQWs of InGaN lLEDs, the use of semipolar structures in InGaN lLEDs has recently been reported. For example, Chen et al. 124 compared c-plane oriented and semipolar (20)(21) InGaN lLEDs and confirmed the advantages of semipolar (20-21) InGaN lLEDs under a high current regime. Figure 8(a) presents a cross-sectional SEM image of semipolar (20-21) GaN on a patterned sapphire substrate used to fabricate semipolar (20)(21) lLEDs. ...
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Electrical-chromatic characteristics of red, green, and blue micro-LEDs (10
$\times$
10
$\mu$
m) are investigated at temperatures ranging from 300 to 340 K. The external quantum efficiency (EQE) of red micro-LEDs decreases significantly with the increasement in temperature, suggesting that heat dissipation is crucial for red micro-LEDs. The impacts of temperature and driving current on the chromaticity coordinates of the light emission from micro-LEDs are determined. When the trichromatic micro-LEDs are driven by the currents corresponding to the maximum EQE, the influence of temperature on the color gamut is limited, facilitating the achievement of high color gamut and high efficiency.
