LED with 3D Nano-Structures for Light Extraction
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Solution Overview
Problem
The extraction efficiency of light emitting diodes (LEDs) is low due to a limited 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 implementation of three-dimensional nano-structures on the semiconductor layers increases the contact area with the active layer, enhancing electron-hole recombination and photon extraction efficiency by creating a patterned surface with protruding structures that increase the light emitting surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a conventional planar structure is used, then the device complexity is low, but the contact area between the N-type semiconductor layer and the active layer is insufficient
Solution Approach 1:
The patent transitions from a two-dimensional planar contact interface to a three-dimensional nanostructured surface. By forming protruding structures (nanopillars, nanowires, or nanodots) on the N-type semiconductor layer, the contact area with the active layer is dramatically increased along the vertical dimension, transforming a flat interface into a vertically extended nanostructured surface that provides multiple contact points.
Solution Approach 2:
The continuous planar surface of the N-type semiconductor layer is segmented into discrete protruding nanostructures. These segmented structures (arranged in arrays) create multiple independent contact regions with the active layer, increasing the total contact area while maintaining structural organization and facilitating improved carrier recombination at multiple interfaces.
2Productivity
If the contact area is increased using three-dimensional nano-structures, then the electron-hole recombination density improves, but the manufacturing process becomes more complex
Solution Approach 1:
The protruding nanostructures are formed on the N-type semiconductor layer before the active layer is deposited. This preliminary structuring allows the subsequent active layer growth to naturally conform to and contact the pre-formed nanostructures, achieving enhanced contact area and recombination density without requiring complex post-processing or alignment steps.
Solution Approach 2:
The epitaxial growth process of the active layer automatically adapts to the pre-formed nanostructure topology. The active layer material naturally deposits on and around the protruding structures, creating self-aligned contacts that maximize the contact area without requiring additional lithography or patterning steps, thereby simplifying the overall manufacturing process.
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 enhanced contact area and patterned surface structure improve the light extraction efficiency of LEDs by increasing the density of electron-hole recombination and photon emission, leading to more efficient light output.
Implementation Method 1
LEDs are semiconductors that convert electrical energy into light... 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
Implementation Method 2
The light emitting surface of the LED defines a plurality of three-dimensional nano structures... enhancing electron-hole recombination and photon extraction efficiency by creating a patterned surface with protruding structures that increase the light emitting surface area
Data Source
AI summary
A light emitting diode including a first semiconductor layer, an active layer, and a second semiconductor layer is provided. The first semiconductor layer includes a first surface and a second surface. The active layer and the second semiconductor layer are stacked on the second surface in that order, and a surface of the second semiconductor layer away from the active layer is configured as the light emitting surface. A first electrode is electrically connected with and covers the first surface of the first semiconductor layer. A second electrode is electrically connected with the second semiconductor layer. A number of three-dimensional nano-structures are located both on the first surface and second surface, and a cross section of each of the three-dimensional nano-structure is M-shaped.