Asymmetric Multi-Quantum Well LED Structure for Electron Blocking
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Solution Overview
Problem
Conventional semiconductor light emitting diodes (LEDs) face issues with electron blocking, leading to high series resistance, reduced conversion efficiency, and poor luminous uniformity due to thick electron blocking layers and high Al content in AlXGa(1-X)N materials, which hinder electron hole transmission and light emission efficiency.
Innovation Solution
A semiconductor light emitting structure with a multi-quantum well (MQW) active layer design, where well and barrier layers near the n-type semiconductor layer have varying thicknesses and energy gaps, and an electron blocking layer is interlaced with these layers to enhance electron restriction and efficiency, using materials like GaN, InGaN, and AlGaN to optimize electron distribution and hole transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electron blocking layer is made thicker or the Al content of AlXGa(1-X)N is increased to improve electron restriction ability, then the electron blocking performance is improved, but the series resistance of the epitaxy stacking structure increases significantly
Solution Approach 1:
The patent applies local quality by creating asymmetric well layer thicknesses within the MQW structure. Specifically, well layers adjacent to the n-type semiconductor layer have a first thickness, while well layers adjacent to the p-type semiconductor layer have a second thickness that is smaller. This local variation in thickness optimizes electron restriction at the n-type interface while maintaining acceptable series resistance and hole transmission throughout the structure.
2Reliability
If the Al content of AlXGa(1-X)N is increased to improve electron blocking, then electron restriction is enhanced, but electron holes find it harder to cross over the electron blocking layer and be transmitted to the active layer
Solution Approach 1:
The patent implements local quality through differential well layer thicknesses in the MQW structure. By making well layers near the n-type layer thicker than those near the p-type layer, the structure achieves strong electron restriction where needed while preserving hole transmission pathways. This localized structural variation allows simultaneous optimization of electron blocking and hole injection without requiring uniformly high Al content throughout the structure.
3Ease of manufacture
If conventional uniform thickness well layers are used in the active layer, then the structure is simpler to manufacture, but the conversion efficiency and luminous uniformity of the active layer are reduced
Solution Approach 1:
The patent applies local quality by introducing asymmetric well layer thicknesses in the MQW active layer structure. Well layers adjacent to the n-type semiconductor layer have a first thickness, while well layers adjacent to the p-type semiconductor layer have a second thickness. This local variation enhances electron restriction capability and improves conversion efficiency and luminous uniformity, while remaining manufacturable through standard MOCVD processes with precise thickness control.
4Ease of manufacture
If conventional uniform thickness well layers are used in the active layer, then manufacturing is easier, but the luminous uniformity of the light emitted by the active layer is poor
Solution Approach 1:
The patent implements local quality through asymmetric well layer thicknesses in the MQW structure. By making well layers near the n-type layer thicker than those near the p-type layer, the structure achieves improved electron restriction and more uniform carrier distribution across the active layer. This results in enhanced luminous uniformity while maintaining compatibility with standard manufacturing processes that can precisely control layer thicknesses.
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 structure effectively restricts electrons within the active layer, enhancing conversion efficiency and luminous uniformity while reducing the series resistance, allowing for lower bias voltage operation and improved light emission characteristics.
Implementation Method 1
The active layer disposed between the n-type semiconductor layer and the p-type semiconductor layer is a multi-quantum well (MQW) structure consisting of a plurality of well layers and a plurality of barrier layers interlaced and stacked to each other
Implementation Method 2
Light emitting diode (LED) is a semiconductor light emitting structure which emits a light by converting electric energy into photo energy
Data Source
AI summary
A semiconductor light emitting structure including an n-type semiconductor layer, a p-type semiconductor layer and an active layer is provided. The active layer disposed between the n-type semiconductor layer and the p-type semiconductor layer is a multi-quantum well structure consisting of well layers and barrier layers interlaced and stacked to each other. The well layers near the n-type semiconductor layer at least include a first well layer having a first thickness, and the well layers near the p-type semiconductor layer at least include a second well layer having a second thickness smaller than the first thickness, so that the ability to restrict electrons within the area of the active layer near the n-type semiconductor layer is increased, and the conversion efficiency of the active layer is enhanced. There is a differential Δd1 between the first thickness and the second thickness, wherein 0 nm<Δd1≦10 nm.