Semiconductor Light Emitter Electrode Layout for Edge Light Extraction
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Solution Overview
Problem
Semiconductor light emitting devices face challenges in maximizing light extraction efficiency and luminous flux due to light absorption issues at the edge regions of the transparent electrode layer, which affects the overall performance and reliability of the devices.
Innovation Solution
The semiconductor light emitting device incorporates a transparent electrode layer spaced apart from the edge of the second conductivity-type semiconductor layer, a first insulating layer with holes, and a reflective electrode layer connected through these holes, along with a connection electrode structure featuring a larger reflective electrode layer and a thinner edge region, enhancing light reflection and extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the transparent electrode layer is disposed close to the edge of the second conductivity-type semiconductor layer, then the device complexity is reduced, but light extraction efficiency deteriorates due to light absorption at edge regions
Solution Approach 1:
The transparent electrode layer is segmented into a central region and edge regions, with the edge regions removed or thinned to reduce light absorption. This segmentation allows the electrode to maintain electrical functionality while improving light extraction at the edges where light absorption was problematic.
Solution Approach 2:
Different regions of the transparent electrode layer are given different properties: the central region maintains full thickness for electrical conductivity, while the edge regions are thinned or removed to reduce light absorption. This local differentiation resolves the contradiction between electrical functionality and optical performance.
2Reliability
If the transparent electrode layer covers the entire second conductivity-type semiconductor layer, then electrical coverage is improved, but light absorption at edge regions increases
Solution Approach 1:
Instead of completely removing the transparent electrode layer at the edges, only a portion is removed or thinned, maintaining partial coverage for electrical reliability while reducing light absorption sufficiently to improve overall light extraction efficiency.
3Loss of energy
If the reflective electrode layer is enlarged to increase reflective area, then light extraction efficiency is improved, but device complexity increases
Solution Approach 1:
The reflective electrode layer is merged with or disposed directly on the insulating layer that already covers the transparent electrode, combining multiple functions into a single integrated structure. This merging increases the reflective area for improved light extraction while avoiding the complexity of separate additional layers.
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 significantly improves light extraction efficiency and luminous flux by reducing light absorption at the edge regions and increasing the reflective area, thereby enhancing the overall performance and reliability of the semiconductor light emitting device.
Implementation Method 1
a reflective electrode layer disposed on the first insulating layer and connected to the transparent electrode layer through the plurality of holes
Implementation Method 2
a transparent electrode layer disposed on the second conductivity-type semiconductor layer and spaced apart from an edge of the second conductivity-type semiconductor layer
Implementation Method 3
a light emitting structure including a first conductivity-type semiconductor layer, an active layer and a second conductivity-type semiconductor layer
Data Source
AI summary
A semiconductor light emitting device includes a light emitting structure having a first conductivity-type semiconductor layer, an active layer and a second conductivity-type semiconductor layer, a transparent electrode layer on the second conductivity-type semiconductor layer and spaced apart from an edge of the second conductivity-type semiconductor layer, a first insulating layer on the light emitting structure to cover the transparent electrode layer and including a plurality of holes connected to the transparent electrode layer, and a reflective electrode layer on the first insulating layer and connected to the transparent electrode layer through the plurality of holes.