Micro-LED Core-Shell Structure for Low-Defect Light Extraction
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Solution Overview
Problem
Current methods for manufacturing LED devices face challenges in achieving high-quality light-emitting layers with low defect density and efficient light extraction, particularly in micro-size LED devices, due to stress-related dislocation issues and limited light extraction efficiency.
Innovation Solution
The method involves growing a light-emitting layer on a crystalized membrane spaced apart from a substrate with a cavity, forming a core-shell structure with a passivation layer to cover the active layer except for specific portions, and creating a convex-concave structure on the top surface for enhanced light extraction, which reduces stress and improves current injection characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light-emitting layer is grown directly on a substrate, then the manufacturing process is simple, but stress-related dislocation occurs leading to high defect density
Solution Approach 1:
A crystalized membrane is introduced as an intermediary layer between the substrate and the light-emitting layer. This membrane serves as a stress buffer that prevents stress-related dislocation from propagating into the light-emitting layer, thereby reducing defect density while maintaining a manageable structure through systematic layering
2Reliability
If a planar structure is used, then the manufacturing process is simple, but light extraction efficiency is limited
Solution Approach 1:
A convex-concave structure is formed on the top surface of the light-emitting layer, replacing the planar geometry with curved surfaces. This curvature increases the light extraction efficiency by reducing total internal reflection and enhancing light emission in multiple directions, while the structured approach maintains manufacturing feasibility
3Reliability
If the active layer is fully covered for protection, then device reliability is improved, but light extraction efficiency decreases
Solution Approach 1:
The passivation layer is selectively applied to cover specific regions of the light-emitting layer while leaving other regions exposed. This local differentiation allows the covered regions to provide protection and current injection, while the exposed regions maintain high light extraction efficiency, optimizing both functions simultaneously
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in high-quality LED devices with improved light extraction efficiency and reliability, enabling the production of micro-size LEDs with enhanced performance and efficiency.
Implementation Method 1
a light-emitting layer (410) spaced apart from the substrate (550) with a cavity (553) therebetween, wherein the light-emitting layer (410) comprises a first semiconductor layer (511), an active layer (513), and a second semiconductor layer (512)
Data Source
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AI summary
Provided are a light-emitting diode (LED) device, a method of manufacturing the LED device, and a display apparatus including the LED device. The LED device includes a light-emitting layer having a core-shell structure, a passivation layer provided to cover a portion of a top surface of the first semiconductor layer, a first electrode provided on the light-emitting layer, and a second electrode provided under the light-emitting layer. The light-emitting layer includes a first semiconductor layer, an active layer, and a second semiconductor layer. The first electrode is provided to contact the first semiconductor layer, and the second electrode is provided to contact the second semiconductor layer.