Nanostructure Semiconductor Light Emitting Device with Graded Indium Quantum Wells
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Solution Overview
Problem
Nanostructure semiconductor light emitting devices face challenges in achieving improved internal quantum efficiency and converting emitted light to longer wavelengths due to problematic indium incorporation during the growth process, which affects luminous efficiency and wavelength emission.
Innovation Solution
The device incorporates a nanostructure design with varying indium composition ratios within quantum wells and adjusts nanocore pitches and sizes to achieve different wavelengths, enabling enhanced internal quantum efficiency and a larger wavelength difference, suitable for multi-wavelength light emission, including white light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If indium incorporation is increased during growth process to achieve longer wavelength emission, then wavelength conversion capability is improved, but internal quantum efficiency deteriorates due to problematic indium incorporation
Solution Approach 1:
The patent applies local quality by creating quantum wells with spatially varying indium composition ratios. Different regions of the active layer have different indium concentrations, allowing simultaneous optimization for both wavelength conversion (requiring higher indium) and internal quantum efficiency (requiring lower indium). This is achieved through multiple quantum well structures with graded indium composition.
Solution Approach 2:
The patent changes the indium composition ratio parameter within quantum wells to achieve different wavelengths. By varying the indium concentration from 0% to up to 50% across different quantum well regions, the device can emit multiple wavelengths including blue, green, yellow, orange, and red light, while maintaining overall device efficiency through optimized structural design.
2Use of energy by moving object
If nanostructure design is used to increase light emission surface area, then luminous efficiency is improved, but control over wavelength emission becomes difficult due to indium incorporation issues
Solution Approach 1:
The patent segments the active layer into multiple quantum well structures, each capable of emitting different wavelengths. This segmentation allows independent optimization of each quantum well's indium composition and thickness, enabling precise wavelength control while maintaining the high surface area benefits of nanostructure design.
Solution Approach 2:
The patent uses composite material structures combining multiple semiconductor layers with different compositions (AlGaN, InGaN, GaN) to create quantum wells with tailored optical properties. This composite approach enables simultaneous achievement of high luminous efficiency through nanostructure design and precise wavelength control through composition engineering.
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 approach significantly improves internal quantum efficiency and achieves a substantial wavelength difference, enabling the production of white light by combining light with different wavelengths, thereby addressing the limitations of existing nanostructure semiconductor light emitting devices.
Implementation Method 1
semiconductor light emitting devices using nanostructures have been developed... can emit light through a significantly large surface area
Implementation Method 2
capable of converting the wavelength of emitted light into a relatively long wavelength
Data Source
AI summary
A nanostructure semiconductor light emitting device includes: a base layer formed of a first-conductivity type nitride semiconductor material; and a plurality of light emitting nanostructures disposed on the base layer to be spaced apart from each other, wherein each of the plurality of light emitting nanostructures includes: a nanocore formed of a first conductivity-type nitride semiconductor material, an active layer disposed on a surface of the nanocore and including a quantum well which is divided into first and second regions having different indium (In) composition ratios in a thickness direction thereof; and a second conductivity-type semiconductor layer disposed on the active layer, and an In composition ratio in the first region is higher than an In composition ratio in the second region.