Multi-Quantum Well Semiconductor Light Emitting Device
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Solution Overview
Problem
Current semiconductor light emitting devices face challenges in enhancing luminance and quantum efficiency, particularly in high current and high output applications, where the efficiency of light emission is limited by the structure of quantum well and barrier layers.
Innovation Solution
The semiconductor light emitting device incorporates a multi-quantum well structure with alternately stacked quantum barrier and well layers, where the thickness of quantum well layers increases towards the p-type semiconductor layer, and the composition of indium in these layers is gradually increased, minimizing thickness differences and optimizing the thickness ratio of well and barrier layers to enhance electron-hole recombination efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the thickness of quantum well layers is increased to improve light output, then luminance is enhanced, but electron leakage increases and quantum efficiency decreases
Solution Approach 1:
The patent applies local quality by creating non-uniform thickness distribution within quantum well layers. Specifically, the first quantum well layer adjacent to the p-type semiconductor layer has a smaller thickness than the second quantum well layer, which in turn has a smaller thickness than the third quantum well layer. This gradual thickness increase from top to bottom optimizes electron-hole recombination efficiency while preventing electron leakage, thereby simultaneously improving luminance and quantum efficiency.
2Illumination intensity
If indium composition is increased in quantum well layers to enhance light emission, then luminance improves, but crystallinity deteriorates
Solution Approach 1:
The patent implements local quality by gradually increasing the indium composition ratio from the first quantum well layer to the third quantum well layer. The first quantum well layer has the lowest indium content, the second has intermediate content, and the third has the highest content. This gradient structure allows each layer to contribute optimally to light emission while maintaining overall crystallinity by avoiding abrupt composition changes.
3Reliability
If multiple quantum well and barrier layers are stacked to improve quantum efficiency, then internal quantum efficiency increases, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the active layer into multiple quantum well layers (first, second, and third quantum well layers) separated by quantum barrier layers. Each quantum well layer is further differentiated by specific thickness and indium composition characteristics. This segmented structure enables independent optimization of each layer's properties to maximize internal quantum efficiency while managing overall device complexity through systematic design.
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 configuration improves luminance and internal quantum efficiency, reduces electron leakage, and enhances light output while maintaining crystallinity, thereby addressing the limitations of existing devices in high current and high output fields.
Implementation Method 1
an active layer disposed between the n-type semiconductor layer and the p-type semiconductor layer, and including a plurality of alternately stacked quantum barrier layers and quantum well layers
Data Source
AI summary
There is provided a semiconductor light emitting device including: an n-type semiconductor layer; a p-type semiconductor layer; and an active layer disposed between the n-type semiconductor layer and the p-type semiconductor layer, and including a plurality of alternately stacked quantum barrier layers and quantum well layers, wherein at least a portion of the plurality of quantum well layers has different thicknesses, wherein a thickness of a first quantum well layer most adjacent to the p-type semiconductor layer is less than a thickness of a second quantum well layer adjacent thereto and greater than a thickness of a third quantum well layer, other than the first and second quantum well layers.