LED Cermet Layer Evanescent Wave Conversion
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Solution Overview
Problem
Semiconductor light emitting diodes (LEDs) face 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
A semiconductor structure is designed with a cermet layer and a protective layer to amplify and extract near-field evanescent waves, utilizing a cermet layer to convert these waves into metallic plasma, which can then be extracted through the substrate, and incorporating three-dimensional nanostructures to improve light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a standard semiconductor structure is used, then the LED has long lifetime and high energy conversion efficiency, but near field evanescent waves are internally reflected causing low light extraction efficiency
Solution Approach 1:
The patent converts the harmful internal reflection of near field evanescent waves into a beneficial effect by introducing a cermet layer that transforms these evanescent waves into propagating light waves through metallic plasma, thereby extracting the previously trapped light energy from the semiconductor structure
Solution Approach 2:
The patent employs a composite cermet layer comprising metal particles embedded in a dielectric matrix, combining the optical properties of both metal and dielectric materials to achieve effective conversion of evanescent waves into extractable light while maintaining structural integrity
2Loss of energy
If the semiconductor structure is modified to extract more light, then light extraction efficiency improves, but the device complexity increases
Solution Approach 1:
The patent segments the light extraction function by introducing a distinct cermet layer between the active layer and the protective layer, separating the light generation function (active layer) from the light extraction function (cermet layer), thereby improving extraction efficiency without complicating the core semiconductor structure
Solution Approach 2:
The cermet layer acts as an intermediary between the active layer and the protective layer, mediating the transformation of evanescent waves into extractable light while maintaining the integrity of the original semiconductor structure and avoiding direct modification of the active region
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 significantly enhances light extraction efficiency by converting near-field evanescent waves into metallic plasma, allowing more photons to be extracted, thereby improving 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
a cermet layer to convert these waves into metallic plasma, which can then be extracted through the substrate
Implementation Method 3
holes in the P-type semiconductor layer and electrons in the N-type semiconductor layer can enter the active layer and combine with each other to emit visible light
Data Source
AI summary
A light emitting diode includes a first semiconductor layer, an active layer, a second semiconductor layer, a protective layer, and a cermet layer. The active layer is on the first semiconductor layer. The second semiconductor layer is on the active layer. the protective layer is located on the semiconductor layer. The cermet layer is located on the protective layer. A first electrode covers entire surface of the first semiconductor layer away from the active layer. A second electrode is electrically connected to the second semiconductor layer.