3D LED Bandgap Gradient for Current Homogeneity
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Solution Overview
Problem
Optoelectronic devices with three-dimensional semiconductor light-emitting diodes face sub-optimal efficiency due to non-homogeneous current distribution caused by non-homogeneous content of elements in electron and hole blocking layers, leading to non-uniform radiation emission.
Innovation Solution
A three-dimensional optoelectronic device with a stack of layers comprising chemical elements, where the mass proportion of specific elements in the charge carrier blocking layer increases or decreases with distance from the substrate, improving the homogeneity of current distribution and radiation emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electron blocking layer and hole blocking layer are used in the active area, then charge carrier blocking function is improved, but non-homogeneous element content causes non-uniform current distribution and reduces light-emitting efficiency
Solution Approach 1:
The patent applies local quality by creating a gradient composition in the blocking layer where the content of the third chemical element varies with distance from the substrate. This gradient structure provides different local properties: near the substrate where current density is higher, the blocking layer has different composition to provide stronger blocking, while farther from the substrate the composition adjusts to maintain homogeneity. This resolves the contradiction by making the blocking function spatially adaptive rather than uniform, thereby maintaining both effective charge carrier blocking and homogeneous current distribution for high light-emitting efficiency.
Solution Approach 2:
The patent implements parameter changes by systematically varying the compositional parameter (content of the third chemical element) of the blocking layer across different spatial positions. The mass proportion of the third chemical element increases or decreases as distance from the substrate increases, creating a controlled gradient. This parameter variation optimizes the blocking layer's electrical properties at different locations, ensuring homogeneous current distribution while maintaining effective charge carrier blocking, thus resolving the efficiency contradiction.
2Ease of manufacture
If uniform composition is used in blocking layers, then manufacturing simplicity is maintained, but non-homogeneous current distribution occurs leading to sub-optimal light-emitting efficiency
Solution Approach 1:
The patent resolves this contradiction by implementing a controlled gradient in the compositional parameter of the blocking layer. Rather than using a uniform composition that is easy to manufacture but performs poorly, or a complex multi-layer structure that improves performance but complicates manufacturing, the invention uses a continuous or stepped gradient of the third chemical element content. This gradient can be achieved through modified deposition techniques where the composition varies systematically with position, providing a balance between manufacturing feasibility and optimal light-emitting efficiency through homogeneous current distribution.
Solution Approach 2:
The patent applies local quality by making the blocking layer's composition dependent on the spatial position relative to the substrate. Different regions of the blocking layer have different compositions optimized for their local electrical conditions. This approach maintains relative manufacturing simplicity compared to complex multi-layer structures while achieving the homogeneous current distribution needed for high light-emitting efficiency, thus resolving the contradiction between ease of manufacture and productivity.
3Stability of the object's composition
If gradient composition is implemented in the blocking layer, then current distribution homogeneity is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by creating a spatially varying composition in the blocking layer that is tailored to the local current distribution requirements. The gradient in the third chemical element content provides different electrical properties at different positions, ensuring homogeneous overall current distribution. This resolves the contradiction by making the composition stability local rather than global, achieving current homogeneity without requiring an overly complex multi-layer structure.
Solution Approach 2:
The patent implements parameter changes in a controlled and systematic manner, varying the third chemical element content as a function of distance from the substrate. This continuous or stepped gradient approach achieves current distribution homogeneity while avoiding the complexity of multiple discrete layers with different compositions. The parameter variation is optimized to provide the necessary electrical properties with minimal structural complexity, resolving the contradiction between composition stability and device complexity.
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 enhances the homogeneity of radiation emission and efficiency of the light-emitting diodes by maintaining a consistent bandgap variation and optimizing the content of elements in the blocking layers, resulting in improved light-emitting diode performance.
Implementation Method 1
the mass proportion of the third and fourth chemical elements of the third layer increasing or decreasing as the distance to the substrate increases... the maximum variation of the bandgap in the third layer is smaller than the maximum variation of the bandgap of a same layer which does not comprise the third chemical element
Data Source
AI summary
An optoelectronic device including: a three-dimensional semiconductor element mostly made of a first chemical element and of a second chemical element; an active area at least partially covering the lateral walls of the three-dimensional semiconductor element and including a stack of at least a first layer mostly made of the first and second chemical elements, and of at least a second layer mostly made of the first and second chemical elements and of a third chemical element; a third layer covering the active area, the third layer being mostly made of the first, second, and third chemical elements and of a fourth chemical element, the mass proportion of the third and fourth chemical elements of the third layer increasing or decreasing as the distance to the substrate increases; and a fourth layer, mostly made of the first and second chemical elements, covering the third layer.