Nitride Semiconductor LED Quantum Barrier Thickness
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Solution Overview
Problem
Green nitride semiconductor LEDs face challenges in achieving high optical efficiency due to lower crystallinity and reduced mobility of electrons and holes, primarily caused by high indium content, which leads to defects and decreased light-emitting efficiency.
Innovation Solution
A nitride semiconductor LED structure with a multi-quantum well active layer, where the quantum barrier layer adjacent to the p-type nitride layer is thinner than the others, improving electron hole mobility while maintaining crystallinity, and the quantum well layers have uniform thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the thickness of quantum barrier layers is increased to improve crystallinity, then crystallinity is improved, but electron and hole mobility deteriorates
Solution Approach 1:
The patent applies local quality by making the quantum barrier layer adjacent to the p-type nitride layer thinner than other quantum barrier layers. This creates a localized region with different thickness properties that facilitates carrier transport while maintaining crystallinity in the overall structure. The selective thinning of specific barrier layers allows different regions to serve different functions: thicker barriers for crystallinity and thinner barriers for mobility.
Solution Approach 2:
The patent segments the quantum barrier layers into two distinct groups with different thicknesses. The first group (adjacent to p-type layer) has reduced thickness to enhance carrier mobility, while the second group maintains standard thickness for crystallinity. This segmentation allows the structure to simultaneously achieve both improved mobility and maintained crystallinity through differentiated layer design.
2Illumination intensity
If indium content is increased to achieve green light emission, then green light emission is achieved, but crystallinity and light-emitting efficiency deteriorate
Solution Approach 1:
The patent applies parameter changes by modifying the thickness parameter of quantum barrier layers adjacent to the p-type nitride layer. By reducing this specific thickness parameter, the structure compensates for the crystallinity degradation caused by high indium content. This parameter adjustment allows green light emission to be achieved while mitigating the negative effects of high indium concentration on crystallinity.
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 enhances the recombination probability of electrons and holes, thereby increasing optical output and stability, avoiding the issues of lower crystallinity and indium content-related defects during GaN growth.
Implementation Method 1
the active layer includes two or more quantum well layers and quantum barrier layers formed in alternation
Implementation Method 2
the recombination probability of electrons and holes in the active layer, i.e. the internal quantum efficiency
Data Source
AI summary
A nitride semiconductor light emitting diode (LED) is disclosed. The nitride semiconductor LED can include an active layer formed between an n-type nitride layer and a p-type nitride layer, where the active layer includes two or more quantum well layers and quantum barrier layers formed in alternation, and the quantum barrier layer formed adjacent to the p-type nitride layer is thinner than the remaining quantum barrier layers. An embodiment of the invention can be used to improve optical efficiency while providing crystallinity in the active layer.