Semiconductor Structure With Metallic Plasma Layer for Light Extraction
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Solution Overview
Problem
Conventional semiconductor structures used for light sources, such as blue, green, and white light sources, 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 structure.
Innovation Solution
The semiconductor structure incorporates a metallic plasma generating layer with a refractive index that amplifies and scatters near field evanescent waves, distributing them uniformly across the structure, combined with optical symmetric layers and three-dimensional nano-structures to enhance light extraction, increasing the interaction between the active layer and metallic plasma, thereby increasing photon production and extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional semiconductor structure is used with N-type and P-type semiconductor layers, then the structure can emit visible light through electron-hole recombination, but the light extraction efficiency is degraded due to internal reflection of near field evanescent waves
Solution Approach 1:
A metallic plasma generating layer is introduced as an intermediary component between the active layer and the external environment. This layer converts near field evanescent waves into propagating light waves through surface plasma resonance, enabling efficient light extraction without requiring complex photonic crystal structures or distributed Bragg reflectors.
Solution Approach 2:
The refractive index of the metallic plasma generating layer is optimized to match the conditions for surface plasma resonance. By controlling the metal layer thickness (typically 5-50 nm) and material composition (such as aluminum, silver, or gold), the structure enables conversion of evanescent waves to propagating waves at specific wavelengths, dramatically improving light extraction efficiency.
2Illumination intensity
If optical symmetric layers are added to enhance light extraction, then the light distribution becomes more uniform, but the device complexity increases
Solution Approach 1:
The patent employs optical symmetric layers with specific refractive indices positioned at defined distances from the metallic plasma generating layer. This controlled asymmetric arrangement creates optical paths that enhance uniform light distribution while maintaining manufacturing simplicity. The symmetric layers act as optical cavities that resonate at specific wavelengths, improving extraction efficiency without requiring complex three-dimensional photonic structures.
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 enhances light extraction efficiency by converting near field evanescent waves into emergent light, improving luminous efficiency and allowing for uniform light distribution across the semiconductor structure.
Implementation Method 1
a metallic plasma generating layer with a refractive index that amplifies and scatters near field evanescent waves
Implementation Method 2
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
Implementation Method 3
A difference between a refractive index of the first optical symmetric layer and a refractive index of the source layer is less than or equal to 0.3
Data Source
AI summary
A semiconductor structure includes a first semiconductor layer, an active layer, a second semiconductor layer, a metallic plasma generating layer, and a first optical symmetric layer stacked in series. The first semiconductor layer, the active layer, and the second semiconductor layer constitute a source layer. A refractive index difference between the source layer and the first optical symmetric layer is less than or equal to 0.3.