LED Cermet Layer Plasmonic Light Extraction
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Solution Overview
Problem
Light emitting diodes (LEDs) using semiconductor structures suffer from low light extraction efficiency due to near-field evanescent waves being internally reflected, leading to a significant portion of emitted light remaining within the semiconductor structure.
Innovation Solution
Incorporating a cermet layer with metallic plasma properties between the active layer and the substrate, which amplifies and converts near-field evanescent waves into extractable photons, and optionally using three-dimensional nanostructures and a protective layer to enhance light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a standard semiconductor structure is used, then the LED structure is simple and easy to manufacture, but the light extraction efficiency is low due to internal reflection of near-field evanescent waves
Solution Approach 1:
A cermet layer is introduced as an intermediary component between the active layer and the electrode. This cermet layer contains metallic nanoparticles that interact with near-field evanescent waves to convert them into extractable photons, thereby improving light extraction efficiency without significantly complicating the manufacturing process
Solution Approach 2:
The cermet layer is composed of a composite material combining metal nanoparticles (such as silver, gold, or aluminum) embedded in a dielectric matrix. This composite structure enables both optical enhancement through plasmonic effects and electrical conductivity for current distribution, addressing multiple functions simultaneously
2Loss of energy
If a cermet layer with metallic plasma properties is added, then light extraction efficiency is improved by converting evanescent waves into photons, but the device complexity increases
Solution Approach 1:
The cermet layer performs multiple functions simultaneously: it extracts light through plasmonic conversion of evanescent waves, distributes current uniformly across the active layer, and can serve as an electrode contact. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity
3Loss of energy
If three-dimensional nanostructures are incorporated, then light extraction efficiency is enhanced through increased surface area and plasma activation, but the manufacturing difficulty increases
Solution Approach 1:
The patent introduces three-dimensional nanostructures (such as nanopyramids, nanorods, or porous structures) that add vertical dimensionality to the cermet layer. This increases the surface area for plasmonic interaction and improves light extraction efficiency, while the self-organizing nature of some nanostructure formation processes helps manage manufacturing complexity
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 cermet layer and nanostructures improve light extraction efficiency by activating metallic plasma, interacting with the active layer to generate additional photons and distribute current uniformly, thereby increasing the overall output of the LED.
Implementation Method 1
Incorporating a cermet layer with metallic plasma properties between the active layer and the substrate, which amplifies and converts near-field evanescent waves into extractable photons
Data Source
AI summary
A method for making light emitting diode includes following steps. A substrate having an epitaxial growth surface is provided. A first semiconductor layer, an active layer, and a second semiconductor layer are epitaxially grown on the epitaxial growth surface of the substrate in that sequence. A cermet layer is formed on the second semiconductor layer. A first electrode is applied to electrically connected to the first semiconductor layer. A second electrode is applied to electrically connected to the second semiconductor layer.