LED Three-Dimensional Nano-Structures for Enhanced Light Extraction
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Solution Overview
Problem
Conventional light emitting diodes (LEDs) have low extraction efficiency due to a small contact area between the N-type semiconductor layer and the active layer, resulting in low electron-hole recombination density and sparse photon emission.
Innovation Solution
The LED design incorporates a substrate with a first semiconductor layer featuring three-dimensional nano-structures, increasing the contact area with the active layer, which enhances electron-hole recombination and photon extraction efficiency. This is achieved by forming M-shaped three-dimensional nano-structures on the surface of the first semiconductor layer, with the active layer and second semiconductor layer stacked on top, and electrodes connected to these layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the contact area between the N-type semiconductor layer and the active layer is increased, then the electron-hole recombination density is improved, but the device structure becomes more complex
Solution Approach 1:
The patent applies dimensionality change by transitioning from a planar contact interface to a three-dimensional nanostructure array. The N-type semiconductor layer is transformed into vertically extending nanostructures that increase the contact area with the active layer from a two-dimensional plane to a multi-dimensional surface, thereby significantly improving electron-hole recombination density without proportionally increasing structural complexity
Solution Approach 2:
The patent utilizes a porous-like nanostructure configuration where the N-type semiconductor layer forms an array of vertical nanostructures with spacing between them. This porous arrangement dramatically increases the surface area and contact interface with the active layer, enabling higher recombination density while maintaining a relatively simple overall device architecture
2Productivity
If the contact area between the N-type semiconductor layer and the active layer is increased, then the photon extraction efficiency is improved, but the manufacturing process becomes more difficult
Solution Approach 1:
The patent employs dimensionality change to create vertically extending nanostructures from the N-type semiconductor layer. This transformation from planar to three-dimensional architecture increases the photon extraction interface area significantly, improving extraction efficiency while using standard semiconductor fabrication techniques to manage manufacturing complexity
Solution Approach 2:
The N-type semiconductor layer is segmented into multiple discrete vertical nanostructures rather than remaining as a continuous planar layer. This segmentation increases the total surface area for photon extraction and electron-hole recombination, while each individual nanostructure can be fabricated using conventional processes, thereby balancing manufacturing ease with performance improvement
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 increased contact area between the semiconductor layers improves electron-hole recombination density and light extraction efficiency, leading to a more effective emission of photons.
Implementation Method 1
The first semiconductor layer 110 defines a plurality of three-dimensional nano-structures 113. The plurality of three-dimensional nano-structures 113 increases a contact area between the first semiconductor layer 110 and the active layer 120
Implementation Method 2
LEDs are semiconductors that convert electrical energy into light. In operation, a positive voltage and a negative voltage are applied respectively to the P-type semiconductor layer and the N-type semiconductor layer. Thus, holes in the P-type semiconductor layer and photons 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 method for making light emitting diode is provided. The method includes following steps. A substrate is provided. A first semiconductor layer is grown on a surface of the substrate. A patterned mask layer is located on a surface of the first semiconductor layer, and the patterned mask layer includes a number of bar-shaped protruding structures, a slot is defined between each two adjacent protruding structures to expose a portion of the first semiconductor layer. The exposed first semiconductor layer is etched to form a protruding pair. A number of three-dimensional nano-structures are formed by removing the patterned mask layer. An active layer and a second semiconductor layers are grown on the number of three-dimensional nano-structures in that order. A first electrode is electrically connected with the first semiconductor layer. A second electrode is electrically connected with the second semiconductor layer.