Semiconductor Light Emitting Device Multi-Interface Reflection
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Solution Overview
Problem
Current semiconductor light emitting devices have limitations in light extraction efficiency, despite efforts to improve this aspect, as they often rely on single interfaces for light reflection, which restricts the overall efficiency of luminescent light extraction.
Innovation Solution
The semiconductor light emitting device incorporates a stacked structural body with a high resistance layer and a transparent conductive layer, where the high resistance layer overlaps with the first electrode, and the transparent conductive layer has a lower refractive index than the second semiconductor layer, enabling light reflection at two interfaces, thereby enhancing light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single interface reflection configuration is used, then the device structure is simple, but the light extraction efficiency is insufficient
Solution Approach 1:
The patent segments the light reflection function into multiple interfaces: a first interface between the light emitting layer and the first electrode, and a second interface between the transparent electrode and the external environment. This segmentation allows light to be reflected at multiple locations, increasing the overall extraction efficiency while maintaining a relatively simple layered structure.
Solution Approach 2:
The patent introduces a transparent electrode layer that extends the light extraction path into a new dimensional space. By placing this transparent electrode above the light emitting layer and creating a second reflection interface, the system utilizes vertical stacking to achieve multi-interface reflection, effectively adding a dimensional aspect to light extraction.
2Loss of energy
If multiple interfaces for light reflection are introduced, then the light extraction efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent merges the light extraction function with the existing electrode structure. The first electrode serves dual purposes: as an electrical contact and as a reflective interface. The transparent electrode is integrated into the stack, combining electrical functionality with optical functionality, thereby reducing overall device complexity while achieving multi-interface reflection.
Solution Approach 2:
The transparent electrode performs multiple functions: it serves as an electrical contact layer, creates a second reflection interface for light extraction, and maintains optical transparency. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity while achieving improved 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 significantly improves light extraction efficiency by utilizing reflections at multiple interfaces, leading to higher luminous efficacy and reduced light loss, compared to devices with single interface reflections.
Implementation Method 1
The transparent conductive layer has a refractive index lower than a refractive index of the second semiconductor layer, enabling light reflection at two interfaces
Implementation Method 2
The high resistance layer has a resistance higher than a resistance of the second semiconductor layer
Implementation Method 3
The transparent conductive layer has a refractive index lower than a refractive index of the second semiconductor layer
Data Source
AI summary
According to one embodiment, a semiconductor light emitting device includes a stacked structural body, first and second electrodes, a high resistance layer and a transparent conductive layer. The stacked structural body includes first and second semiconductor layers and a light emitting layer. The first semiconductor layer is disposed between the first electrode and the second semiconductor layer. The second semiconductor layer is disposed between the second electrode and the first semiconductor layer. The second electrode has reflectivity with respect to luminescent light. The high resistance layer is in contact with the second semiconductor layer between the second semiconductor layer and the second electrode and includes a portion overlapping with the first electrode. The transparent conductive layer is in contact with the second semiconductor layer between the second semiconductor layer and the second electrode. The transparent conductive layer has a resistance lower than a resistance of the high resistance layer.