LED with AlInGaN Electron Blocking Layers

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Solution Overview

Problem

Conventional light emitting diodes (LEDs) face challenges in achieving high brightness and efficiency due to crystal defects and excessive electron injection, leading to reduced luminous intensity and increased operating voltage.

Innovation Solution

The design incorporates a light emitting structure with a first semiconductor layer, an active layer, an intermediate layer with p-type doped AlxGa1-xN, and a second semiconductor layer, featuring a quantum well structure and a cart-shaped barrier layer to enhance hole injection efficiency and prevent electron overflow, thereby improving light emission efficiency and reducing operating voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional LED structures are used, then manufacturing is simpler, but light emission efficiency is reduced due to crystal defects and electron overflow

Engineering Contradiction:
Improvestructure simplicityVSAvoidlight emission efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The LED structure is segmented into multiple functional layers including n-type AlInGaN electron blocking layers positioned at specific locations (first electron blocking layer between active layer and n-type GaN layer, second electron blocking layer between n-type AlInGaN layer and n-type GaN layer). This segmentation allows each layer to perform its specific function of preventing electron overflow while maintaining manufacturing feasibility through standardized layer deposition processes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The n-type AlInGaN electron blocking layers act as intermediary elements between the active layer and the n-type GaN layer. These intermediate layers have specific bandgap energies that create potential barriers to prevent electron overflow into the n-type GaN layer, thereby improving light emission efficiency without requiring complete restructuring of the basic LED architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If conventional LED structures are used, then device complexity is lower, but operating voltage increases due to excessive electron injection

Engineering Contradiction:
Improvelayer structure complexityVSAvoidoperating voltage
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The electron blocking function is segmented across multiple layers: the first electron blocking layer (n-type AlInGaN) is positioned adjacent to the active layer, and the second electron blocking layer (n-type AlInGaN) is positioned between the first electron blocking layer and the n-type GaN layer. This segmented approach creates multiple potential barriers that collectively reduce electron overflow and operating voltage more effectively than a single thick blocking layer.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the material composition parameter by using AlInGaN alloy with specific aluminum content to create electron blocking layers with appropriate bandgap energies. By adjusting the aluminum composition ratio, the potential barrier height is optimized to prevent electron overflow while maintaining acceptable operating voltage and manufacturing feasibility.

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If brightness is increased for home use and rescue signals, then luminous intensity improves, but crystal defects increase reducing efficiency

Engineering Contradiction:
Improveluminous intensityVSAvoidcrystal quality
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The n-type AlInGaN electron blocking layers are positioned beforehand at critical interfaces (between active layer and n-type GaN layer, and between first electron blocking layer and n-type GaN layer) to prevent electron overflow before it can cause crystal defects. This prior protection mechanism allows the LED to operate at high currents for high luminous intensity while maintaining crystal quality by preventing the accumulation of excess electrons that would otherwise create defects.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 solution results in higher luminous intensity and lower operating voltage for LEDs, addressing the limitations of conventional LEDs by optimizing carrier injection and recombination processes.

Implementation Method 1

an intermediate layer disposed between the active layer and the second semiconductor layer, wherein the intermediate layer comprises P type doped Al x Ga 1-x N

Methodology Applied
Scientific EffectElectron blocking:

Implementation Method 2

A light emitting diode (LED) is a device that converts an electrical signal into infrared light, visible light or other forms of light using the properties of a compound semiconductor

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP2551923B1Light emitting diode
Publication Date: 2019.12.11 LG INNOTEK CO LTD
  • EP2551923B1 patent drawingFigure 1
  • EP2551923B1 patent drawingFigure 2
  • EP2551923B1 patent drawingFigure 3~4

AI summary

A light emitting diode (100) is disclosed. In the light emitting diode, the structure of a barrier layer of an active layer (130) is changed, and a band gap energy of an intermediate layer (140) is varied, thereby improving hole injection efficiency of the active layer and thus light emission efficiency.