LED Active Layer Barrier Thickness and Doping Gradient
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Solution Overview
Problem
Current light emitting diodes (LEDs) face challenges in enhancing internal quantum efficiency, which limits their light emitting efficiency, despite ongoing studies on modifying materials and structures.
Innovation Solution
The LED design includes an active layer with barrier layers that are at least twice as thick as the well layers, and a doping strategy where the first barrier layer adjacent to the p-type semiconductor is partially doped with n-type impurity, while the second barrier layers are fully doped, with the doping concentration decreasing towards the second region adjacent to the p-type semiconductor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional quantum well structure with thin barrier layers is used, then device complexity is low, but internal quantum efficiency is insufficient
Solution Approach 1:
The barrier layer is segmented into multiple regions with different thicknesses and doping concentrations. The first barrier layer has a first thickness and first doping concentration, while the second barrier layer has a second thickness and second doping concentration, creating a graded structure that improves electron injection efficiency progressively
Solution Approach 2:
Different regions of the barrier layer are assigned different local properties: the first barrier layer near the n-type semiconductor has higher doping concentration and specific thickness to enhance electron injection, while the second barrier layer has different parameters optimized for its position, creating localized quality improvements throughout the structure
2Reliability
If uniform doping is applied throughout the barrier layer, then manufacturing precision is high, but electron injection efficiency is insufficient
Solution Approach 1:
The doping concentration varies locally within the barrier layer structure. The first barrier layer has a first doping concentration optimized for electron injection from the n-type semiconductor, while the second barrier layer has a second doping concentration optimized for its position, allowing localized optimization without requiring complete restructuring
Solution Approach 2:
The doping concentration parameter is changed progressively from the first barrier layer to the second barrier layer. This parameter variation optimizes electron injection efficiency at each interface while maintaining manufacturability through controlled gradient changes rather than abrupt transitions
3Reliability
If barrier layer thickness is increased to enhance electron injection, then internal quantum efficiency improves, but manufacturing precision requirements increase
Solution Approach 1:
The total barrier layer thickness is segmented into multiple discrete layers with different thicknesses. The first barrier layer has a first thickness and the second barrier layer has a second thickness, allowing each layer to be manufactured within standard precision tolerances while achieving the cumulative effect of enhanced electron injection
Solution Approach 2:
Instead of requiring a single thick barrier layer with precise thickness control, the parameter is changed by creating multiple layers with different thicknesses. This gradient approach to thickness variation achieves the desired electron injection enhancement while relaxing the precision requirements for any single layer
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 increases the electric field applied to the active layer, enhancing electron injection and thereby improving internal quantum efficiency and overall light emitting efficiency.
Implementation Method 1
This configuration increases the electric field applied to the active layer, enhancing electron injection
Implementation Method 2
the first barrier layer adjacent to the p-type semiconductor is partially doped with n-type impurity, while the second barrier layers are fully doped
Implementation Method 3
light emitting diodes (LEDs) emit light of a visible wavelength band or near-infrared and infrared wavelength bands by applying a forward current to a p-n junction formed on a group-III or group-V compound semiconductor wafer
Implementation Method 4
The active layer 30 has a quantum well structure where well layers 31 and barrier layers 32 are alternately laminated
Data Source
Figure 1~2A
Figure 2B~3
Figure 4A~4B
AI summary
Provided are a light emitting diode (LED) and a method for manufacturing the same. The LED includes an n-type semiconductor layer, an active layer, and a p-type semiconductor layer. The active layer includes a well layer and a barrier layer that are alternately laminated at least twice. The barrier layer has a thickness at least twice larger than a thickness of the well layer.