Semiconductor Light Emitting Device Uneven Electrode Structure

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional semiconductor light emitting devices face challenges in enhancing external quantum efficiency and adhesive strength between semiconductor layers, particularly due to the flatness of electrode layers which limits light extraction and reliability.

Innovation Solution

The introduction of a discontinuous first semiconductor layer with an uneven structure and a second electrode layer having a corresponding uneven shape, along with a conductive support member, enhances light reflection and extraction by altering the critical angle of incident light, thereby improving external quantum efficiency and adhesive strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a flat second electrode layer is used, then the manufacturing process is simple, but the external quantum efficiency is low due to limited light extraction

Engineering Contradiction:

Improveelectrode layer fabrication simplicityVSAvoidexternal quantum efficiency

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The second electrode layer is formed with an uneven surface having protrusions and recesses instead of a flat surface. This curved/uneven structure increases the critical angle for light extraction, allowing more light to escape from the semiconductor layer, thereby improving external quantum efficiency while maintaining manufacturing feasibility through standard deposition techniques

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The surface morphology parameter of the second electrode layer is changed from flat to uneven by controlling deposition conditions or using self-assembly processes. This parameter change increases light extraction efficiency by creating multiple interfaces with different critical angles, resolving the contradiction between manufacturing simplicity and device performance

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If a flat second electrode layer is used, then the structure is simple, but the adhesive strength between electrode and semiconductor layer is insufficient

Engineering Contradiction:

Improveelectrode structure complexityVSAvoidadhesive strength

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

The uneven surface structure of the second electrode layer creates increased surface area and mechanical interlocking features (protrusions and recesses) that enhance adhesive bonding between the electrode and the underlying semiconductor layer, thereby improving strength without significantly increasing structural complexity

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The second electrode layer exhibits local variations in surface topology with protrusions and recesses distributed across the layer. These local structural differences create multiple bonding interfaces and increase contact area with the semiconductor layer, enhancing overall adhesive strength while maintaining overall structural simplicity

Inventive Principle:

Principle #3Local quality

3Device complexity

If the critical angle for light extraction is not optimized, then the device structure remains conventional, but light extraction efficiency is limited

Engineering Contradiction:

Improvelight extraction structureVSAvoidlight extraction efficiency

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The uneven surface structure of the second electrode layer creates multiple critical angles for light extraction across different regions of the surface. Light rays incident at various angles can find extraction paths through the protrusions and recesses, reducing total internal reflection losses and improving overall light extraction efficiency without requiring complex additional structures

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The natural tendency of light to undergo total internal reflection at flat interfaces (which causes energy loss) is converted into a benefit by introducing an uneven surface structure. The same optical principles that cause reflection at flat surfaces are exploited through curved/uneven interfaces to create extraction pathways, turning the harmful reflection effect into useful light extraction

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 significantly increases external quantum efficiency and electrical reliability by optimizing light extraction and adhesive properties, making the semiconductor light emitting device more effective as a light source in various applications.

Implementation Method 1

enhances light reflection and extraction by altering the critical angle of incident light

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS8421101B2Semiconductor light emitting device

Publication Date: 2013.04.16 BOE HC SEMITEK LTD (HENGQIN)

AI summary

Provided are a semiconductor light emitting device and a method for manufacturing the same. The semiconductor light emitting device comprises a first electrode on an region of top surface of a first conductive semiconductor layer; a second electrode layer under a second conductive semiconductor layer; and a conductive support member under the second electrode layer, wherein the second conductive semiconductor layer includes a plurality of recesses on a lower portion of the second conductive semiconductor layer, wherein the second electrode layer has an uneven structure corresponding to the plurality of recesses.