GaN Quantum Well Structure for Low Voltage High Output
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Solution Overview
Problem
Gallium nitride-based compound semiconductor light-emitting devices face challenges in achieving low operating voltage while maintaining good emission output, as existing technologies often result in decreased emission efficiency due to regions without quantum dots or boxes having low resistance and preferential current application, leading to poor output.
Innovation Solution
A gallium nitride-based compound semiconductor multilayer structure with a multiple quantum well structure featuring well layers of uniform and ununiform thickness, where the well layers closest to the p-type and n-type layers are uniformly thick, and the barrier layers are composed of GaN or AlGaN with dopants, to optimize emission efficiency and reduce operating voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the thickness of the well layer is adjusted to 2 to 3 nm in a multiple quantum well structure, then satisfactory emission output is attained, but a problematically high operating voltage is required
Solution Approach 1:
The patent applies local quality by creating spatial variation in well layer thickness within the quantum well structure. Specifically, the well layer thickness is designed to vary from a first thickness in a first region to a second thickness in a second region, allowing different portions of the structure to contribute differently to emission output and operating voltage characteristics, thereby resolving the contradiction between achieving high emission output and maintaining low operating voltage.
2Ease of manufacture
If a quantum dot structure is formed using the anti-surfactant effect, then emission efficiency of each light-emitting dot is improved, but regions without quantum dots have extremely low resistance causing preferential current application and decreased overall emission output
Solution Approach 1:
The patent applies homogeneity by ensuring uniform thickness of the well layer throughout the entire light-emitting layer, including regions above and below the quantum dots. This uniform structure ensures that current is distributed evenly across all regions, preventing the preferential current application to low-resistance areas and thereby improving overall emission output while maintaining the emission efficiency benefits of the quantum dot structure.
3Illumination intensity
If quantum dots are formed in a light-emitting layer, then light emission is enhanced, but the structure complexity increases and manufacturing precision requirements increase
Solution Approach 1:
The patent applies self-service by utilizing the anti-surfactant effect during the semiconductor layer formation process itself to automatically create quantum dots without requiring separate fabrication steps. The quantum dots form naturally through the self-organization of surfactant molecules during crystal growth, which eliminates the need for additional complex manufacturing processes and reduces precision requirements while still achieving enhanced light emission.
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 structure achieves a balance of low operating voltage and high emission output by ensuring uniform thickness in critical well layers and using dopants in barrier layers, preventing wavelength shift and maintaining peak inverse voltage characteristics.
Implementation Method 1
a light-emitting layer having a multiple quantum well structure in which a well layer and a barrier layer are alternately stacked repeatedly
Implementation Method 2
the barrier layers are composed of GaN or AlGaN with dopants
Data Source
AI summary
The object of the present invention is to provide a gallium nitride-based compound semiconductor multilayer structure useful for manufacturing a gallium nitride-based compound semiconductor light-emitting device which requires a low operating voltage and from which a good emission output can be obtained. The present gallium nitride-based compound semiconductor multilayer structure comprises a substrate having thereon an n-type layer, a light-emitting layer and a p-type layer, the light-emitting layer having a multiple quantum well structure in which a well layer and a barrier layer are alternately stacked repeatedly and the light-emitting layer being provided between the n-type layer and the p-type layer, wherein the well layers consisting of the multiple quantum well structure comprise a well layer having an ununiform thickness and a well layer having a uniform thickness.