UV Nitride Quantum Well Structure for Higher Emission Efficiency

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Solution Overview

Problem

Current nitride semiconductor light emitting elements that emit ultraviolet light have lower light emission efficiency compared to those emitting visible light.

Innovation Solution

A nitride semiconductor light emitting element is designed with an active layer structure that includes a first barrier layer, a first well layer, a second barrier layer, and a second well layer, where the second well layer has a higher Al composition ratio and is thinner than the first well layer, and an electron blocking layer is added to reduce electron overflow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a conventional active layer structure is used in ultraviolet light emitting elements, then the device can be manufactured with standard processes, but the light emission efficiency is lower compared to visible light emitting elements

Engineering Contradiction:
Improvelight emission efficiencyVSAvoidactive layer structure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The active layer is segmented into multiple quantum well layers (first quantum well layer and second quantum well layer) separated by barrier layers. This segmentation allows optimization of carrier confinement and recombination efficiency in each layer, thereby improving light emission efficiency while managing structural complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different quantum well layers are designed with different Al composition ratios tailored to their specific functions. The first quantum well layer has a specific Al composition optimized for its emission characteristics, while the second quantum well layer has a different Al composition optimized for carrier confinement and interaction with the electron blocking layer, achieving local optimization of light emission efficiency

Inventive Principle:
Principle #3Local quality

2Loss of energy

If the Al composition ratio and thickness of quantum well layers are optimized for ultraviolet emission, then light emission efficiency improves, but manufacturing precision requirements increase

Engineering Contradiction:
Improvelight emission efficiencyVSAvoidlayer thickness and composition control
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The invention optimizes specific parameters of the quantum well layers including Al composition ratio and thickness to enhance ultraviolet light emission efficiency. By carefully controlling these parameters during manufacturing, the patent achieves improved emission efficiency while establishing clear fabrication guidelines

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If an electron blocking layer is added to reduce electron overflow, then light emission efficiency improves, but device complexity increases

Engineering Contradiction:
Improvelight emission efficiencyVSAvoidlayer structure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

An electron blocking layer is extracted and positioned between the p-side cladding layer and the second quantum well layer. This separate functional layer is specifically designed to block electron overflow into the p-side region, preventing carrier loss and improving light emission efficiency while maintaining a clear functional separation in the device structure

Inventive Principle:
Principle #2Taking out (Extraction)

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 ultraviolet light emission efficiency of the nitride semiconductor light emitting element, achieving improved performance compared to existing technologies.

Implementation Method 1

an active layer positioned between the n-side semiconductor layer and the p-side semiconductor layer... the first well layer containing Al and emitting ultraviolet light, a second well layer disposed in contact with the electron blocking layer, containing Al, and emitting ultraviolet light

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP4496012A1Nitride semiconductor light emitting element and method of manufacturing same
Publication Date: 2025.01.22 NICHIA CORP
  • EP4496012A1 patent drawingFigure 1
  • EP4496012A1 patent drawingFigure 2~3
  • EP4496012A1 patent drawingFigure 4~5

AI summary

A nitride semiconductor light emitting element includes: an n-side semiconductor layer; a p-side semiconductor layer; an active layer positioned between the n-side semiconductor layer and the p-side semiconductor layer; and an electron blocking layer positioned between the p-side semiconductor layer and the active layer. The active layer includes, successively from the n-side semiconductor layer side: a first barrier layer containing Al, a first well layer that contains Al and emits ultraviolet light, a second barrier layer containing Al, and a second well layer that is in contact with the electron blocking layer, contains Al, and emits ultraviolet light. An Al composition ratio of the second well layer is higher than an Al composition ratio of the first well layer. A thickness of the second well layer is less than a thickness of the first well layer.