Light Emitting Device Facet Tilt Angle Current Distribution
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Solution Overview
Problem
Semiconductor light emitting devices with nano-structures face challenges in efficiently injecting electrical current due to concentrated electrical fields at sharp tip portions, leading to localized current density increases and reduced light emission efficiency.
Innovation Solution
A light emitting device with a laminated structure featuring columnar parts having specific tilt angles and bandgap configurations for the semiconductor layers, which relaxes electrical field concentration and facilitates efficient current injection by using tilt angles and c-planes to distribute the electrical current more evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the microcrystalline prismatic crystal has a sharp tip portion (facet structure), then the radiation angle becomes narrow and light emission intensity increases, but the electrical field concentrates at the sharp portion causing localized current density increase and reduced current injection efficiency
Solution Approach 1:
The patent applies local quality by creating different facet structures at different locations within the light emitting layer. Specifically, the light emitting layer includes a first region with a first facet structure and a second region with a second facet structure, where the facet angles or orientations differ between regions. This allows different local areas to have optimized properties: some regions optimized for light emission intensity while others optimized for current distribution, thereby resolving the contradiction between narrow radiation angle/high intensity and efficient current injection.
Solution Approach 2:
The patent segments the light emitting layer into multiple regions with different facet structures. By dividing the layer into a first region and a second region, each with distinct facet characteristics, the patent enables independent optimization of different functional requirements within the same device structure, allowing simultaneous achievement of high light emission intensity and efficient current injection.
2Stability of the object's composition
If the active layer has a sharp tip portion to achieve narrow radiation angle, then the photonic crystal effect is enhanced, but the electrical field concentration causes uneven current distribution and reduces overall device efficiency
Solution Approach 1:
The patent implements local quality by assigning different facet structures to different regions of the light emitting layer. The first region has a first facet structure optimized for maintaining stable radiation angle, while the second region has a second facet structure optimized for ensuring uniform current distribution. This regional differentiation allows both stability and reliability requirements to be satisfied simultaneously.
Solution Approach 2:
The patent employs asymmetry by creating facet structures with different orientations or angles in different regions. The first facet structure and second facet structure are intentionally made asymmetric relative to each other, allowing each region to fulfill its specific functional requirement while contributing to the overall device performance.
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
The solution effectively reduces electrical field concentration, allowing for efficient current injection and improved light emission efficiency by distributing the current more evenly across the light emitting layer, enhancing the device's performance.
Implementation Method 1
a light emitting layer disposed between the first semiconductor layer and the second semiconductor layer... the light emitting layer includes a first layer, and a second layer larger in bandgap than the first layer
Implementation Method 2
the microcrystalline prismatic crystal has a facet structure in a tip portion... the electrical field is concentrated into the sharp portion
Data Source
AI summary
In a light emitting device, a columnar part includes a first semiconductor layer, a second semiconductor layer different in conductivity type from the first semiconductor layer, and a light emitting layer disposed between the first semiconductor layer and the second semiconductor layer, the first semiconductor layer is disposed between the substrate and the light emitting layer, the light emitting layer includes a first layer, and a second layer larger in bandgap than the first layer, the first semiconductor layer has a facet plane, the first layer has a facet plane, the facet plane of the first semiconductor layer is provided with the first layer, and θ2>θ1, in which θ1 is a tilt angle of the facet plane of the first semiconductor layer with respect to a surface of the substrate provided with the laminated structure, and θ2 is a tilt angle of the facet plane of the first layer provided to the facet plane of the first semiconductor layer with respect to the surface of the substrate.