LED Super Lattice and Nano-Structure for Stress Relief
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Solution Overview
Problem
Conventional light emitting diodes (LEDs) have limited light emitting efficiency due to high quantum dropping effects and epitaxy defects, which are exacerbated by stress between the substrate and semiconductor layers, resulting in lower internal and external quantum efficiencies compared to cold cathode fluorescent lamps.
Innovation Solution
A light emitting diode device with a silicon-based substrate incorporating a super lattice structure layer and a nano-structure layer is developed, where the super lattice structure, composed of thin layers of aluminum gallium nitride/gallium nitride, buffers stress and reduces epitaxy defects, while the nano-structure layer enhances light scattering, thereby increasing quantum efficiencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional LED structure is used, then the device is simple and easy to manufacture, but the light emitting efficiency is limited due to high quantum dropping effects and epitaxy defects
Solution Approach 1:
The patent divides the semiconductor layer into multiple segments: a first semiconductor layer with high crystal orientation and a second semiconductor layer with lower crystal orientation. This segmentation allows each layer to serve different functions - the first layer provides high efficiency light emission while the second layer acts as a buffer to reduce stress and quantum dropping effects, thereby resolving the contradiction between structural simplicity and light emitting efficiency
Solution Approach 2:
The patent changes the crystal orientation parameter between layers, with the first semiconductor layer having a first crystal orientation and the second semiconductor layer having a second crystal orientation different from the first. This parameter change enables the structure to simultaneously achieve high light emitting efficiency in the first layer and stress buffering in the second layer
2Illumination intensity
If the thickness of semiconductor layers is increased to improve light output, then the light emitting effect is enhanced, but stress between substrate and semiconductor layers increases causing more epitaxy defects
Solution Approach 1:
The patent segments the semiconductor structure into multiple layers with different thicknesses and crystal orientations. The first semiconductor layer can be optimized for light output while the second semiconductor layer serves as a stress buffer, allowing the overall structure to achieve high light output without excessive stress accumulation
Solution Approach 2:
The second semiconductor layer acts as an intermediary between the substrate and the light-emitting first semiconductor layer. It buffers the stress transmitted from the substrate, preventing stress-induced epitaxy defects while allowing the first layer to maintain optimal thickness for high light output
3Reliability
If the crystal orientation of semiconductor layers is optimized for light emission, then internal quantum efficiency increases, but stress concentration increases leading to more defects
Solution Approach 1:
The patent segments the semiconductor structure into layers with different crystal orientations. The first semiconductor layer has a crystal orientation optimized for high internal quantum efficiency, while the second semiconductor layer has a different crystal orientation that provides stress buffering, thus resolving the contradiction between efficiency and stress concentration
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 solution effectively reduces quantum dropping effects, increases epitaxy quality, and enhances both internal and external quantum efficiencies, leading to improved light emitting efficiency and scattering effects in the LED device.
Implementation Method 1
the super lattice structure layer is formed on the buffer layer... the super lattice structure in the light emitting diode is mainly used to buffer the stress between the substrate and the first semiconductor GaN layer
Implementation Method 2
the nano-structure layer enhances light scattering, thereby increasing quantum efficiencies... The light scattering effect of the light emitting layer towards the silicon-based substrate is increased
Implementation Method 3
the light emitting diode is the light emitting device which is able to convert the electric energy into the light energy directly... After the voltage is applied to both ends of this p-n junction, the electrons and holes will flow towards this p-n junction immediately, and bond together to release the photons
Data Source
AI summary
A light emitting diode device is provided, which comprises a silicon-based substrate, a buffer layer, a super lattice structure layer, a nano-structure layer, a first semiconductor layer, a light emitting layer, and a second semiconductor layer. The buffer layer is formed on the silicon-based substrate, the super lattice structure layer is formed on the buffer layer, the nano-structure layer is formed on the super lattice structure layer, a first semiconductor layer is formed on the nano-structure layer, and the light emitting layer is formed between the first semiconductor layer and the second semiconductor layer. The super lattice layer and the nano-structure can release the stress within the light emitting diode device, and reduce the epitaxy defect, so that the internal quantum effect and the external quantum effect can be increased.