LED Nano-Structure Contact Area Enhancement
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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 formation of three-dimensional nano-structures on the surface of the semiconductor layer increases the contact area with the active layer, enhancing electron-hole recombination and photon extraction efficiency by creating a patterned surface for improved light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a conventional planar structure is used between the N-type semiconductor layer and the active layer, then the device structure is simple, but the contact area is insufficient resulting in low electron-hole recombination density and low light extraction efficiency
Solution Approach 1:
The patent transforms the planar two-dimensional contact interface into a three-dimensional nano-structure surface. By forming vertical nano-pillars, nano-cones, or nano-wires on the N-type semiconductor layer, the contact area is extended from a flat surface to a multi-dimensional nano-structured surface, dramatically increasing the effective contact area between the N-type layer and active layer for enhanced electron-hole recombination
Solution Approach 2:
The patent divides the continuous N-type semiconductor layer surface into discrete nano-structures (nano-pillars, nano-cones, or nano-wires). This segmentation creates multiple independent contact points with the active layer, increasing the overall contact area and providing distributed pathways for electron-hole recombination, thereby improving light extraction efficiency
2Productivity
If the contact area between N-type semiconductor layer and active layer is increased, then the electron-hole recombination density and light extraction efficiency are improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent performs preliminary patterning of the N-type semiconductor layer before growing the active layer. By pre-forming the nano-structure pattern on the N-type layer, the subsequent active layer growth naturally conforms to this pattern, creating the desired three-dimensional contact interface without requiring complex post-processing steps or additional manufacturing complexity
Solution Approach 2:
The patent replaces complex mechanical or lithographic patterning methods with chemical vapor deposition or molecular beam epitaxy processes. The active layer is grown to conformally cover the pre-formed nano-structures on the N-type layer, utilizing self-organization and vapor-phase deposition mechanisms to achieve the three-dimensional contact structure with simpler manufacturing steps
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 and patterned surface design significantly improve the light extraction efficiency of LEDs by increasing electron-hole recombination density and photon emission.
Implementation Method 1
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 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, and the first surface is connected to the substrate. 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 covers the entire 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 on the surface of the first surface of the first semiconductor layer and aligned side by side, and a cross section of each of the three-dimensional nano-structure is M-shaped.