III-Nitride Quantum Well Structure for Stable Red LED Emission
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Solution Overview
Problem
Existing LED displays face issues with optoelectronic characteristics mismatch of red, green, and blue light LED chips, particularly concerning light-emitting efficiency, blue shift phenomenon, and full-width at half-maximum (FWHM) of the light-emitting wavelength.
Innovation Solution
A semiconductor structure comprising a first and second semiconductor stack, an active structure with alternately stacked group III nitride barrier and quantum well layers, and an aluminum-containing cap layer or interlayer, which enhances light-emitting efficiency, reduces blue shift, and narrows the FWHM of the light-emitting wavelength, especially for wavelengths greater than 600 nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional LED chip structures are used, then manufacturing simplicity is maintained, but optoelectronic characteristics mismatch occurs among red, green, and blue light LED chips
Solution Approach 1:
The patent applies parameter changes by precisely controlling the thickness of group III nitride barrier layers (200-550 angstroms) and quantum well layers, and by adjusting aluminum content in cap layers and interlayers. These parameter optimizations enable consistent optoelectronic characteristics across red, green, and blue LED chips while maintaining manufacturability
Solution Approach 2:
The patent employs composite material structures combining group III nitride barrier layers, quantum well layers, aluminum-containing cap layers, and pre-strain stacks with alternating sublayers. This composite approach enables tailored optoelectronic properties for different wavelength LEDs while using compatible material systems
2Productivity
If standard quantum well structures are used, then manufacturing process simplicity is maintained, but light-emitting efficiency is insufficient
Solution Approach 1:
The active structure is segmented into multiple functional layers: group III nitride barrier layers, quantum well layers, aluminum-containing cap layers, and pre-strain stacks. This segmentation allows each layer to be optimized independently for carrier confinement, recombination efficiency, and strain management, achieving high light-emitting efficiency
Solution Approach 2:
Different regions of the semiconductor structure are assigned different compositions and properties: barrier layers provide carrier confinement, quantum well layers provide recombination zones, aluminum-containing layers provide strain compensation and optical field confinement. This local optimization of quality parameters maximizes light-emitting efficiency
3Reliability
If conventional LED structures are used, then device simplicity is maintained, but blue shift phenomenon occurs
Solution Approach 1:
Pre-strain stacks are introduced before the active structure to pre-compensate for strain that would otherwise cause blue shift during operation. The alternating first and second sublayers in the pre-strain stacks are designed to counteract the compressive strain in the active structure, stabilizing the emission wavelength
Solution Approach 2:
The pre-strain stacks provide counter-strain to balance the compressive strain in the active structure. By introducing tensile strain in the pre-strain stacks, the net strain on the quantum well layers is reduced, minimizing blue shift phenomenon
4Manufacturing precision
If conventional LED structures are used, then manufacturing simplicity is maintained, but FWHM of light-emitting wavelength is excessive
Solution Approach 1:
The FWHM is reduced by optimizing critical parameters: barrier layer thickness (200-550 angstroms), quantum well layer thickness, aluminum content in cap layers, and pre-strain stack composition. These parameter controls narrow the emission spectrum while maintaining manufacturing feasibility
Solution Approach 2:
Aluminum-containing cap layers and pre-strain stacks act as intermediary structures that mediate between the quantum well layers and the external environment. They provide strain compensation, optical field confinement, and stress management, resulting in narrower FWHM
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 proposed semiconductor structure significantly improves light-emitting efficiency, reduces the blue shift phenomenon, and narrows the FWHM of the light-emitting wavelength, resulting in enhanced optoelectronic performance for LED displays.
Implementation Method 1
The active structure emits light with a wavelength greater than 600 nm
Data Source
AI summary
A semiconductor structure includes a first semiconductor stack having a first conductivity type, a second semiconductor stack having a second conductivity type, an active structure disposed between the first semiconductor stack and the second semiconductor stack, and an aluminum-containing cap layer in the active structure. The active structure includes a plurality of group III nitride barrier layers and a plurality of group III-nitride quantum well layers which are alternately stacked. The thickness of the group III-nitride barrier layers is ranged between 200 angstroms to 550 angstroms, and the aluminum-containing cap layer is disposed between the group III nitride quantum well layers and the group III nitride barrier layers, and the active structure has a wavelength of at least 600 nm.