InAlGaN Superlattice Electron Blocking Layer for LED Efficiency

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Solution Overview

Problem

The light emitting efficiency of LEDs is degraded due to lattice mismatch between the active layer and the electron blocking layer, leading to reduced hole injection efficiency and increased carrier leakage.

Innovation Solution

Incorporating an InxAlyGa1-x-yN based superlattice layer between the active layer and the second conductivity-type semiconductor layer to minimize energy band bending and electrostatic field, thereby improving hole injection efficiency and reducing carrier leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the thickness of the electron blocking layer is increased to improve electron blocking, then electron overflow is reduced, but carrier leakage increases and light emitting efficiency is degraded

Engineering Contradiction:

Improveelectron blocking capabilityVSAvoidcarrier leakage

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The electron blocking layer is divided into multiple thin alternating layers of AlGaN and InGaN, each with optimized thickness. This segmentation allows the total effective blocking thickness to be achieved while distributing the stress and electrostatic field across multiple interfaces, preventing excessive field buildup that would cause carrier leakage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The superlattice structure changes the effective parameters of the electron blocking layer, including the average composition ratio, layer thickness, and interface density. These parameter changes optimize the balance between electron blocking capability and electrostatic field distribution, reducing carrier leakage while maintaining efficient electron blocking.

Inventive Principle:

Principle #35Parameter changes

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 InxAlyGa1-x-yN based superlattice layer enhances hole injection efficiency, minimizes carrier leakage, and reduces operating voltage, resulting in improved light emitting efficiency and reduced thickness of the electron blocking layer.

Implementation Method 1

hole injection efficiency may be improved by decreasing the bending of an energy band in a valance band

Methodology Applied

Scientific EffectEnergy band bending:

Implementation Method 2

carrier leakage can be minimized by reducing the electrostatic field between the active layer and the electron blocking layer

Methodology Applied

Scientific EffectElectrostatic field: Electric Field

Data Source

PatentUS10510925B2Light-emitting device and lighting system comprising same

Publication Date: 2019.12.17 SUZHOU LEKIN SEMICON CO LTD

AI summary

Embodiments relate to a light emitting device, a light emitting device package, and a lighting system comprising the same. The light emitting device according to embodiments may comprise: a first conductivity-type semiconductor layer; an active layer on the first conductivity-type semiconductor layer; an electron blocking layer on the active layer; and a second conductivity-type semiconductor layer on the electron blocking layer. The electron blocking layer may comprise an InxAlyGa1-x-yN based superlattice layer (wherein 0≤x≤1, 0≤y≤1).