Nitride LED Layer Structure for Lattice-Matched Radiative Recombination

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Solution Overview

Problem

Existing light-emitting diodes (LEDs) face challenges in achieving high luminous efficiency due to lattice mismatch and defects in quantum well and barrier layers, leading to reduced radiative recombination of electrons and holes.

Innovation Solution

A light-emitting device with a stress relief structure composed of alternately stacked narrow and wide band gap layers, an active structure with quantum well and barrier layers, and an electron blocking structure, all made of nitride semiconductor materials, to improve lattice matching and enhance electron distribution and recombination efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If quantum well and barrier layers are stacked to form an active structure, then light emission function is achieved, but lattice mismatch and defects reduce radiative recombination efficiency

Engineering Contradiction:

Improveradiative recombination efficiencyVSAvoidlattice matching quality

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

A stress relief structure comprising narrow band gap layers and wide band gap layers alternately stacked is introduced between the substrate and the active structure. This intermediary structure gradually transitions the lattice constant, reducing the lattice mismatch between the substrate and the quantum well layers, thereby decreasing dislocation density and improving radiative recombination efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The stress relief structure utilizes alternating layers with different band gaps and aluminum compositions to gradually change the lattice parameter from the substrate to the active structure. By controlling the aluminum composition gradient in the narrow and wide band gap layers, the lattice mismatch is progressively reduced, improving the quality of the active structure.

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If aluminum composition in wide band gap layer is increased to improve band gap configuration, then electron distribution is optimized, but manufacturing complexity increases

Engineering Contradiction:

Improveelectron recombination efficiencyVSAvoidlayer structure complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The wide band gap layer is segmented into multiple sub-layers with different aluminum compositions. This segmentation allows the aluminum composition to be gradually increased from the interface with the quantum well layer toward the outer region, optimizing electron distribution while maintaining controllable manufacturing complexity through systematic composition grading.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the wide band gap layer are assigned different aluminum compositions to achieve local optimization of electron distribution. The aluminum composition is higher near the quantum well interface where electron confinement is needed, and gradually decreases toward the outer region, creating a localized electron distribution optimization without uniformly increasing complexity throughout the entire structure.

Inventive Principle:

Principle #3Local quality

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 structure enhances the radiative recombination of electrons and holes, improving the luminous efficiency of the LED by reducing lattice defects and optimizing band gap configurations.

Implementation Method 1

improve lattice matching and enhance electron distribution and recombination efficiency

Methodology Applied

Scientific EffectLattice matching:

Implementation Method 2

enhances the radiative recombination of electrons and holes, improving the luminous efficiency

Methodology Applied

Scientific EffectRadiative recombination:

Implementation Method 3

an electron blocking structure on the active structure

Methodology Applied

Scientific EffectElectron blocking:

Data Source

PatentUS12507505B2Light-emitting device

Publication Date: 2025.12.23 ENNOSTAR CORP

AI summary

A light-emitting device includes a first nitride semiconductor structure; a stress relief structure on the first nitride semiconductor structure including a plurality of narrow band gap layers and a plurality of wide band gap layers alternately stacked, wherein one of the plurality of wide band gap layers includes a plurality of wide band gap sub-layers and one of the plurality of wide band gap sub-layers includes aluminum; an active structure on the stress relief structure including a plurality of quantum well layers and a plurality of barrier layers alternately stacked, wherein one of the plurality of barrier layers includes a plurality of barrier sub-layers and one of the plurality of barrier sub-layers includes aluminum, an aluminum composition of the wide band gap sub-layer is greater than or equal to that of the barrier sub-layer, and an average aluminum composition of the wide band gap layer is greater than that of the barrier layer; and an electron blocking structure on the active structure.