Semiconductor Light-Emitting Device with Segmented Metal Electrode
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Solution Overview
Problem
Conventional semiconductor light-emitting devices face limitations in enhancing luminance intensity due to heat generation issues, as increased current leads to decreased luminance intensity and heat buildup, and existing heat-sinking substrates are ineffective in cooling the heated areas close to the light-emitting region.
Innovation Solution
A semiconductor light-emitting device with a metal electrode layer having openings and a light-extraction layer, where the metal electrode layer is formed with a continuous metal part and openings to improve heat dissipation and reduce series resistance, and the light-extraction layer is designed to increase light transmittance and reduce reflection loss, using materials like ZnS with a fine rugged structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If current is increased to enhance luminance intensity, then luminance intensity increases up to a certain value, but heat generation increases and luminance intensity decreases beyond that value
Solution Approach 1:
The metal electrode is divided into multiple segments with openings between them, allowing heat to be dissipated through the openings while maintaining current conduction paths. This segmentation enables heat removal from the active region without compromising electrical connectivity.
Solution Approach 2:
The metal electrode structure is designed with different local properties: continuous metal regions for current conduction and openings for heat dissipation. This local differentiation allows simultaneous optimization of electrical and thermal performance in different areas of the electrode.
2Temperature
If a heat-sinking substrate is provided on the bottom of the device, then cooling is improved, but the substrate is positioned too far from the heated part to be effective
Solution Approach 1:
Heat dissipation openings are created in the metal electrode at the location where heat is generated, enabling preliminary heat removal before it can accumulate. This prevents heat buildup at the source rather than attempting to remove it later at a distant substrate.
3Area of stationary object
If the pad electrode is enlarged to expand the light-emitting part, then the light-emitting area increases, but the electrode structure becomes complicated requiring additional thin wire electrodes
Solution Approach 1:
The metal electrode is designed to perform multiple functions simultaneously: it serves as the current supply electrode, the light-emitting surface, and the heat dissipation structure. The openings in the electrode enable both current conduction and heat removal, eliminating the need for separate cooling structures or wire electrodes.
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 device achieves improved heat dissipation and luminance intensity by evenly distributing current across the semiconductor layer, reducing heat generation and enhancing light extraction, resulting in brighter luminescence and lower forward voltage.
Implementation Method 1
the metal electrode layer is formed with a continuous metal part and openings to improve heat dissipation
Implementation Method 2
the light-extraction layer is designed to increase light transmittance and reduce reflection loss, using materials like ZnS with a fine rugged structure
Implementation Method 3
the semiconductor light-emitting device generally includes electrodes and a semiconductor layer placed between them, and emits luminescence when current flows between the electrodes
Data Source
AI summary
A semiconductor light-emitting device according to the embodiment includes a substrate, a compound semiconductor layer, a metal electrode layer provided with particular openings, a light-extraction layer, and a counter electrode. The light-extraction layer has a thickness of 20 to 120 nm and covers at least partly the metal part of the metal electrode layer; or otherwise the light-extraction layer has a rugged structure and covers at least partly the metal part of the metal electrode layer. The rugged structure has projections so arranged that their summits are positioned at intervals of 100 to 600 nm, and the heights of the summits from the surface of the metal electrode layer are 200 to 700 nm.