Semiconductor Light Emitting Device Electrode Inversion
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Solution Overview
Problem
Conventional semiconductor light emitting devices face reduced luminous efficiency due to limited light extraction and increased optical absorption, particularly in high-power devices with large areas, resulting from the electrode-to-substrate area ratio and non-conductive substrates.
Innovation Solution
A semiconductor light emitting device with a conductive substrate, a first electrode layer, an insulating layer, a second electrode layer, a second semiconductor layer, an active layer, and a first semiconductor layer are sequentially stacked, with the first electrode layer penetrating through contact holes to the first semiconductor layer, and the insulating layer separating the electrodes from the active and semiconductor layers, optimizing the contact area and light reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-conductive substrate is used with electrodes formed on semiconductor layers, then electrical connection is achieved, but light extraction is limited and optical absorption increases reducing luminous efficiency
Solution Approach 1:
The patent inverts the conventional electrode arrangement by placing electrodes on the substrate rather than on the semiconductor layers. This inversion allows the light-emitting surface to be free of electrodes, improving light extraction efficiency while maintaining electrical connection through the substrate.
Solution Approach 2:
The substrate serves as an intermediary that provides both mechanical support and electrical connection. By forming electrodes on the substrate and using conductive pathways through the substrate, the patent achieves electrical connection without placing electrodes on the light-emitting semiconductor surface.
2Ease of operation
If electrode area is increased to improve current spreading, then current distribution improves, but light emitting area is reduced and luminous efficiency decreases
Solution Approach 1:
The patent moves the electrodes from the light-emitting surface (2D plane) to the substrate plane (different dimension), allowing current spreading to occur at the substrate level without occupying the light-emitting area. This dimensional separation resolves the conflict between current spreading and light emission area.
3Power
If device area is increased for high-power operation, then power output increases, but optical absorption increases and luminous efficiency decreases
Solution Approach 1:
The patent segments the device into distinct functional zones: electrode regions on the substrate for electrical connection and current injection, and a free light-emitting surface for optimal light extraction. This segmentation allows large-area devices to maintain high luminous efficiency by preventing electrode-related optical absorption in the light-emitting region.
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 enhances luminous efficiency by improving current spreading and reducing optical absorption, allowing for stable operation at high currents while maintaining high luminous efficiency.
Implementation Method 1
the first electrode layer penetrates the second electrode layer, the second semiconductor layer, and the active layer and is electrically connected to the first semiconductor layer
Implementation Method 2
The insulating layer insulates the first electrode layer from the second electrode layer, the second semiconductor layer and the active layer by being provided between the first electrode layer and the second electrode layer
Implementation Method 3
light emitting diodes (LEDs) are devices that use diodes, to which semiconductors are bonded, convert energy generated by the recombination of electrons and holes into light, and emit the light
Implementation Method 4
A semiconductor light emitting device with a conductive substrate, a first electrode layer, an insulating layer, a second electrode layer, a second semiconductor layer, an active layer, and a first semiconductor layer are sequentially stacked
Data Source
AI summary
There is provided a semiconductor light emitting device including a conductive substrate, a first electrode layer, an insulating layer, a second electrode layer, a second semiconductor layer, an active layer, and a first semiconductor layer that are sequentially stacked. The contact area between the first electrode layer and the first semiconductor layer is 3% to 13% of the total area of the semiconductor light emitting device, and thus high luminous efficiency is achieved.