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, reducing the overall emission of visible light.
Innovation Solution
Incorporating a cermet layer with metallic plasma properties between the active layer and the substrate, which amplifies and extracts near-field evanescent waves as metallic plasma, enhancing light extraction efficiency by interacting with the quantum well to produce additional photons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a standard semiconductor structure is used for LED, then the device 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:
The patent introduces a cermet layer as an intermediary component between the active layer and the substrate. This cermet layer contains metallic nanoparticles that interact with near-field evanescent waves, converting them into propagating light waves that can be extracted from the LED. The intermediary layer mediates the energy transfer from the semiconductor structure to extractable light, resolving the contradiction between simple structure and high light extraction efficiency.
Solution Approach 2:
The patent employs a cermet composite material consisting of metallic nanoparticles dispersed in a dielectric matrix. This composite material combines the optical properties of metals (plasmonic resonance) with dielectrics (low loss), enabling efficient conversion of evanescent waves to propagating waves. The composite material approach allows achieving high light extraction efficiency while maintaining a relatively simple device structure.
2Illumination intensity
If the active layer emits near-field evanescent waves, then the quantum well produces light, but the evanescent waves are internally reflected and remain trapped in the semiconductor structure
Solution Approach 1:
The patent converts the harmful internal reflection of near-field evanescent waves into a beneficial effect by using the cermet layer's plasmonic resonance. The metallic nanoparticles in the cermet layer couple with the evanescent waves, extracting their energy and converting it into propagating light waves that can escape the semiconductor structure. This transforms the previously harmful trapped energy into useful extractable light.
Solution Approach 2:
The patent changes the optical parameters of the interface between the active layer and the substrate by introducing the cermet layer with specific metallic nanoparticle composition and size. This parameter change modifies the refractive index profile and enables plasmonic resonance, fundamentally altering how near-field evanescent waves interact with the structure to convert trapped energy into extractable light.
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 significantly improves light extraction efficiency by converting near-field evanescent waves into metallic plasma, increasing the emission of visible light and reducing internal reflection, thereby enhancing the overall performance of the LED.
Implementation Method 1
near field evanescent waves emitted from the active layer are internally reflected inside the semiconductor structure
Implementation Method 2
Incorporating a cermet layer with metallic plasma properties between the active layer and the substrate, which amplifies and extracts near-field evanescent waves as metallic plasma
Implementation Method 3
which amplifies and extracts near-field evanescent waves as metallic plasma, enhancing light extraction efficiency by interacting with the quantum well to produce additional photons
Implementation Method 4
near field evanescent waves emitted from the active layer are internally reflected inside the semiconductor structure, so that a large portion of the light emitted from the active layer remain in the semiconductor structure
Data Source
AI summary
A light emitting diode includes a substrate, a buffer layer, a first semiconductor layer, an active layer, a second semiconductor layer, and a cermet layer. The active layer is on the first semiconductor layer. The second semiconductor layer is on the active layer. The cermet layer is on the second semiconductor layer. A first electrode is electrically connected to the first semiconductor layer. A second electrode is electrically connected to the second semiconductor layer.