LED Intermediate Layer Refractive Index Design
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Solution Overview
Problem
Conventional light-emitting diodes (LEDs) face challenges in optimizing light-extraction efficiency due to limitations in the design of their semiconductor structures, particularly in the interaction between intermediate layers and conductivity-type semiconductor layers, which affects the escape of radiation and overall performance.
Innovation Solution
A light-emitting device with a semiconductor structure comprising a first and second conductivity-type semiconductor layer, alternated well and barrier layers, and intermediate layers with specific refractive index differences and thicknesses, where the intermediate layers are in direct contact with the conductivity-type semiconductor layers, enhancing light-extraction efficiency by controlling radiation escape and reducing internal reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional semiconductor structures are used in LEDs, then the device complexity is low, but the light-extraction efficiency is insufficient due to limitations in radiation escape
Solution Approach 1:
The semiconductor structure is segmented into multiple functional layers including first and second conductivity-type semiconductor layers, alternated well and barrier layers, and first and second intermediate layers. This segmentation allows each layer to perform specific functions in optimizing light extraction, with the intermediate layers having different refractive index differences to control radiation escape at different interfaces.
Solution Approach 2:
Different intermediate layers are designed with different refractive index characteristics - the first intermediate layer has a smaller refractive index difference with its adjacent semiconductor layer compared to the second intermediate layer. This local quality variation optimizes light extraction at different locations within the device structure.
2Productivity
If intermediate layers with optimized refractive index differences are introduced, then light-extraction efficiency is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes specific parameters including the thickness of intermediate layers (first thickness and second thickness, both greater than barrier layer thickness) and refractive index differences between layers. By carefully controlling these parameters, the design achieves improved light extraction while providing clear fabrication guidelines for manufacturing.
3Productivity
If the active region comprises alternated well layers and barrier layers with specific thicknesses, then internal quantum efficiency is enhanced, but the device complexity increases
Solution Approach 1:
The active region is segmented into alternated well layers and barrier layers, creating a multi-layer quantum well structure. This segmentation enables improved carrier confinement and recombination efficiency, directly enhancing internal quantum efficiency while distributing the structural complexity across multiple functional sub-layers.
Solution Approach 2:
The active region uses composite semiconductor materials with different bandgap energies arranged in alternating well and barrier layers. This composite structure optimizes carrier injection and recombination processes, improving internal quantum efficiency through material composition rather than simply increasing structural 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 described configuration improves light-extraction efficiency and internal quantum efficiency by optimizing the thickness and refractive index differences of the intermediate and conductivity-type semiconductor layers, leading to enhanced radiation escape and reduced forward voltage.
Implementation Method 1
a first difference between a refractive index of the first intermediate layer and a refractive index of the first conductivity-type semiconductor layer is less than a second difference between a refractive index of the second intermediate layer and a refractive index of the second conductivity-type semiconductor layer
Data Source
AI summary
A light-emitting device comprises a semiconductor structure comprising a first conductivity-type semiconductor layer, a second conductivity-type semiconductor layer, a first intermediate layer, a second intermediate layer, and an active region capable of emitting radiation, wherein the active region is between the first intermediate layer and the second intermediate layer, the first intermediate layer is in direct contact with the first conductivity-type semiconductor layer, the second intermediate layer is in direct contact with the second conductivity-type semiconductor layer, and the active region comprises alternated well layers and barrier layers, wherein each barrier layer has a thickness; wherein a first difference between a refractive index of the first intermediate layer and a refractive index of the first conductivity-type semiconductor layer is less than a second difference between a refractive index of the second intermediate layer and a refractive index of the second conductivity-type semiconductor layer.