Non-overlapping Contact Layer Optoelectronic Device
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Solution Overview
Problem
Current LED technologies face challenges in enhancing luminous efficiency, particularly in increasing light extraction efficiency (LEE) and internal quantum efficiency (IQE), which limits their energy conservation and carbon emission reduction potential in lighting applications.
Innovation Solution
The development of an optoelectronic device with a semiconductor stack structure featuring a second contact layer comprising semiconductor material dots that do not overlap with the first contact layer, enhancing current spreading and light extraction through a combination of semiconductor materials and layer structures, including a MQW structure and omnidirectional reflecting structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional LED structure is used, then manufacturing is simple, but light extraction efficiency is low
Solution Approach 1:
The contact layer is segmented into multiple discrete contact regions (first contact layer and second contact layer) positioned at different locations on the semiconductor stack. This segmentation allows light emitted in certain directions to escape without being absorbed by continuous contact material, thereby improving light extraction efficiency while maintaining manufacturing feasibility through standard photolithography processes.
Solution Approach 2:
The patent introduces a vertical dimension separation between contact layers by positioning the first contact layer on one surface and the second contact layer on the opposite surface of the semiconductor stack. This spatial arrangement in three-dimensional space enables light extraction paths that avoid contact layer absorption, resolving the contradiction between simple structure and high light extraction efficiency.
2Reliability
If contact layers are overlapped in vertical direction, then electrical contact is improved, but light extraction efficiency decreases
Solution Approach 1:
The contact structure is divided into spatially separated first and second contact layers that do not overlap vertically. Each contact layer provides electrical connection at its respective surface, ensuring reliable electrical contact while the spatial separation creates light extraction pathways that avoid absorption by contact materials.
Solution Approach 2:
The patent applies different functional qualities to different regions: the first contact layer region provides electrical contact at the first surface, while the second contact layer region provides electrical contact at the second surface. The non-overlapping configuration creates local regions optimized for light extraction, resolving the conflict between electrical contact reliability and light extraction efficiency.
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 configuration achieves high optical efficiency, with optical efficiencies ranging from 70 to 121 lumen/watt, depending on chip size, and improves radiant power by up to 15% compared to conventional devices, effectively addressing the limitations in existing LED technologies.
Implementation Method 1
The LED luminous efficiency can be increased through several aspects. One is to increase the internal quantum efficiency (IQE) by improving the epitaxy quality to enhance the combination efficiency of electrons and holes.
Implementation Method 2
Another is to increase the light extraction efficiency (LEE) that emphasizes on the increase of light which is emitted by the light-emitting layer capable of escaping outside the device
Data Source
AI summary
An optoelectronic device includes a semiconductor stack including a first surface and a second surface opposite to the first surface; a first contact layer on the first surface; and a second contact layer on the second surface. The second contact layer is not overlapped with the first contact layer in a vertical direction. The second contact layer includes a plurality of dots separating to each other and formed of semiconductor material.