Semiconductor LED Current Spreading via Segmented Blocking Layers
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Solution Overview
Problem
Conventional light-emitting diodes (LEDs) suffer from poor brightness enhancement due to excessive current concentration, which limits their light-emitting efficiency.
Innovation Solution
A semiconductor light-emitting device design featuring a substrate with epitaxial layers, current blocking layers, and a current spreading layer, where the current spreading layer covers the first current blocking layer, and electrodes with elongated extension portions and convex structures to distribute current evenly, along with an adhesion enhancement layer for improved electrical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a current blocking layer is used under the P-type electrode to block current, then the current is forced to bypass the current blocking layer and be spread out by a transparent conductive layer, improving brightness, but the current becomes too concentrated in certain areas, resulting in poor brightness enhancement effect
Solution Approach 1:
The current blocking layer is segmented into multiple isolated blocking regions rather than a continuous layer. These discrete blocking regions are distributed across the device, forcing current to flow through multiple paths around each region, thereby achieving more uniform current distribution while maintaining effective current blocking functionality
Solution Approach 2:
Different regions of the device are given different functional qualities: some areas have current blocking functionality while others have current spreading functionality. The current blocking layer is strategically positioned in specific local regions to control current flow patterns, while transparent conductive layers in other regions facilitate current spreading, creating an optimized local quality distribution throughout the device
2Productivity
If conventional current blocking structure is used, then current can be blocked and spread, but the brightness enhancement effect is poor due to concentrated current areas
Solution Approach 1:
The patent introduces a multi-layer vertical structure with current blocking layers, transparent conductive layers, and reflective layers arranged in different dimensional levels. This three-dimensional arrangement allows current to be controlled and distributed through multiple spatial dimensions, transforming the conventional two-dimensional current flow into a more complex three-dimensional path that enhances brightness distribution
Solution Approach 2:
Transparent conductive layers and reflective layers are introduced as intermediary elements between the current blocking layer and the light-emitting regions. These intermediary layers mediate the current flow by providing additional conduction paths and reflecting current back into active regions, thereby enhancing the brightness enhancement effect while maintaining current blocking functionality
Data Source
AI summary
A semiconductor light-emitting device includes: a substrate, an epitaxial layer structure disposed on the substrate, a first current blocking layer disposed on the epitaxial layer structure, a second current blocking layer disposed on the epitaxial layer structure, a current spreading layer disposed on the epitaxial layer structure and covering the first current blocking layer; a first electrode disposed on a side of the current spreading layer facing away from the epitaxial layer structure, and a second electrode disposed on the epitaxial layer structure and covering the second current blocking layer. The first current blocking layer includes a first main blocking portion and a first extended blocking portion. The second current blocking layer includes a second main blocking portion and a second extended blocking portion. The second extended blocking portion includes spacings. The first extended blocking portion is formed with convex structures. The convex structures are aligned with the spacings.