Semiconductor Light Extraction via Metallic Plasma Conversion
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Solution Overview
Problem
Conventional semiconductor structures used for light sources, such as those made from gallium nitride, suffer from low light extraction efficiency due to near-field evanescent waves being internally reflected, leading to a significant portion of emitted light being trapped within the structure.
Innovation Solution
The semiconductor structure incorporates a metallic layer as an optical symmetric center, with refractive index-matched layers and three-dimensional nano-structures to amplify and scatter near-field evanescent waves, enhancing light extraction efficiency by converting them into metallic plasma and uniformly distributing it across the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional semiconductor structure is used with N-type and P-type layers, then the device 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:
The patent converts the harmful near-field evanescent waves that are normally internally reflected and trapped into useful extracted light by introducing a metallic layer that transforms them into metallic plasma, which then radiates light outward, turning the previously harmful trapped energy into beneficial light output
Solution Approach 2:
The patent changes the optical parameters of the semiconductor structure by introducing a metallic layer with specific refractive index properties and creating three-dimensional nano-structures, which modifies the refractive index distribution and enables transformation of evanescent waves into propagating light modes
2Use of energy by moving object
If refractive index-matched layers are added to improve light extraction, then the light extraction efficiency increases, but the device structure becomes more complex
Solution Approach 1:
The patent creates a composite structure combining semiconductor layers with a metallic layer and three-dimensional nano-structures, where the metallic component provides unique plasma oscillation properties that cannot be achieved with conventional dielectric materials alone, enabling enhanced light extraction through a different physical mechanism
3Use of energy by moving object
If three-dimensional nano-structures are introduced to amplify and scatter evanescent waves, then light extraction efficiency is enhanced, but the manufacturing process becomes more difficult
Solution Approach 1:
The patent transitions from two-dimensional planar semiconductor layers to three-dimensional nano-structures with vertical and lateral features, adding a third dimension to the structure that enables scattering and amplification of evanescent waves through multiple interfaces and paths, thereby enhancing light extraction efficiency
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 light extraction efficiency by uniformly distributing metallic plasma and increasing the electron-hole recombination density, leading to improved luminous efficiency and light output.
Implementation Method 1
near field evanescent waves emitted from the active layer are internally reflected inside the semiconductor structure
Implementation Method 2
amplify and scatter near-field evanescent waves, enhancing light extraction efficiency by converting them into metallic plasma
Implementation Method 3
refractive index-matched layers and three-dimensional nano-structures to amplify and scatter near-field evanescent waves
Implementation Method 4
near field evanescent waves emitted from the active layer are internally reflected inside the semiconductor structure
Implementation Method 5
amplify and scatter near-field evanescent waves
Implementation Method 6
three-dimensional nano-structures to amplify and scatter near-field evanescent waves
Implementation Method 7
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 semiconductor structure includes a first semiconductor layer, a active layer, a second semiconductor layer, a third optical symmetric layer, a metallic layer, a fourth optical symmetric layer, and a first optical symmetric layer stacked in sequence. The first semiconductor layer, the active layer, and the second semiconductor layer constitute a source layer. A refractive index of the third optical symmetric layer or the fourth optical symmetric layer is in a range from about 1.2 to about 1.5. A refractive index difference between the source layer and the first optical symmetric layer is less than or equal to 0.3.