Semiconductor Light-Emitting Device Current Spreading
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Solution Overview
Problem
Conventional semiconductor light-emitting devices experience reduced light extraction efficiency due to current concentration on local regions, leading to non-uniform light emission and degraded device characteristics, especially with larger devices, where the refractive index mismatch between the light-transmitting conductive film and insulator results in reduced reflection and light refraction.
Innovation Solution
Incorporating a high-resistance body with openings in the light-transmitting conductive film to improve current spreading and light uniformity, where the high-resistance body is made of materials with a lower refractive index than the conductive film, allowing for better light reflection and emission from the semiconductor light-emitting device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a light-transmitting conductive film with insulator is used under pad electrodes, then current spreading is improved, but light extraction efficiency is reduced due to refraction at the interface
Solution Approach 1:
The patent applies local quality by creating openings in the light-transmitting conductive film at specific locations corresponding to pad electrodes and branch electrodes. This allows the conductive film to have different properties in different regions: intact in light-emitting regions for high light extraction, and opened in electrode regions for improved current spreading and reduced refraction losses.
Solution Approach 2:
The light-transmitting conductive film is segmented by creating multiple openings through it. These openings divide the continuous film into separate regions, allowing light to pass through unobstructed in certain areas while maintaining electrical connectivity in others. This segmentation resolves the contradiction by enabling both functions simultaneously in different spatial locations.
2Power
If the device area is increased for higher power consumption, then power output is improved, but current concentration on local regions occurs leading to non-uniform light emission
Solution Approach 1:
Branch electrodes are introduced to segment the current path across the larger device area. Multiple branch electrodes distribute the current more evenly across the expanded active region, preventing concentration at single pad electrodes and maintaining uniform light emission despite increased device size and power consumption.
Solution Approach 2:
The patent transitions from a simple two-pad electrode configuration to a multi-dimensional electrode network with multiple branch electrodes arranged across the device. This dimensional expansion of the electrode structure enables better current distribution across larger areas, maintaining emission uniformity as device size increases.
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 enhances light extraction efficiency and maintains low operating voltage by increasing the reflection factor and light emission, while preventing excessive reduction of the light emission area, thus improving the overall performance of semiconductor light-emitting devices.
Implementation Method 1
the refractive index (e.g., 1.8-2.0) of the light-transmitting conductive film, which is made of ITO, etc., is greater than the refractive index (e.g., 1.5) of the insulator, which is made of SiO2, etc. As such, light is refracted on the interface between the insulator and the light-transmitting conductive film, and the reflection factor of light is reduced
Implementation Method 2
The III-nitride semiconductor light-emitting device includes a substrate 10 (e.g., sapphire substrate), a buffer layer 20 grown on the substrate 10, an n-type III-nitride semiconductor layer 30 grown on the buffer layer 20, an active layer 40 grown on the n-type III-nitride semiconductor layer 30
Data Source
AI summary
The present disclosure relates to a semiconductor light-emitting device, which includes: a plurality of semiconductor layers composed of a first semiconductor layer, a second semiconductor layer, and an active layer; a first electrode disposed on the second semiconductor layer; a high-resistance body interposed between the second semiconductor layer and the first electrode; and a light-transmitting conductive film having an opening through which the high-resistance body is exposed, the first electrode being brought into contact with the light-transmitting conductive film, which is disposed on the high-resistance body, and the high-resistance body, which is exposed through the opening.