UV Light Emitting Device With Segmented Barrier Layers
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Solution Overview
Problem
Current light emitting devices struggle to efficiently emit ultraviolet light with a peak wavelength in the range of 285 nm to 385 nm, which is essential for various applications including display and lighting systems, due to limitations in carrier confinement and recombination rates.
Innovation Solution
A light emitting device structure comprising a first and second conductivity type semiconductor layer with an active layer featuring multiple well and barrier layers, where the barrier layers have specific energy bandgaps and aluminum content to enhance electron confinement and recombination efficiency, emitting ultraviolet light within the desired wavelength range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor layer structures are used, then device simplicity is maintained, but internal quantum efficiency and carrier confinement are insufficient for effective UV light emission
Solution Approach 1:
The active layer is segmented into multiple quantum well layers (first well layer W1, second well layer W2, third well layer W3) separated by barrier layers. Each quantum well layer is further divided into multiple segments (e.g., first segment W1-1, second segment W1-2) with different Al contents, creating a segmented structure that enhances carrier confinement and recombination efficiency for UV light emission.
Solution Approach 2:
Different regions of the quantum well layers have different Al contents optimized for their specific functions. The first segment (W1-1, W2-1, W3-1) has higher Al content (5-30%) for better barrier properties, while the second segment (W1-2, W2-2, W3-2) has lower Al content (0-5%) for better carrier confinement. This local quality variation optimizes overall device performance.
2Reliability
If simple barrier layers are used, then manufacturing is easier, but electron confinement and recombination rates are insufficient
Solution Approach 1:
The barrier layers are segmented into multiple sub-layers (first barrier layer B1, second barrier layer B2, third barrier layer B3) with different Al contents and thicknesses. Each barrier layer segment is optimized for specific carrier confinement functions, improving overall recombination efficiency while maintaining manufacturability through standardized deposition processes.
Solution Approach 2:
The barrier layers are constructed as composite structures combining AlGaN materials with different Al compositions. This composite approach creates optimized energy band profiles that enhance carrier confinement and recombination efficiency without requiring complex fabrication steps, as all layers are grown using standard MOCVD or MBE techniques.
3Illumination intensity
If high Al content is used in quantum well layers, then UV light emission is enhanced, but lattice mismatch and dislocation increase
Solution Approach 1:
The quantum well layers are segmented into multiple sections with progressively varying Al contents. The first segment has higher Al content (5-30%) for UV emission enhancement, while the second segment has lower Al content (0-5%) to reduce lattice mismatch. This gradual transition minimizes dislocation formation while maintaining high UV light emission intensity.
Solution Approach 2:
The Al content parameter is systematically varied across different segments and layers to optimize both UV emission and lattice matching. By changing the Al composition parameter from 0-30% across different regions, the patent achieves high UV light intensity while controlling lattice mismatch and dislocation density through controlled parameter gradients.
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 proposed structure significantly improves internal quantum efficiency and luminous intensity by optimizing carrier confinement and recombination rates, enabling effective ultraviolet light emission within the 285 nm to 385 nm range.
Implementation Method 1
An LED (Light Emitting Device) is a device to convert electrical energy into light energy
Implementation Method 2
the active layer including a plurality of well layers and a plurality of barrier layers, wherein the plurality of well layers comprise a first well layer (W1) and a second well layer (W2) adjacent to the first well layer (W1)
Implementation Method 3
the first barrier layer comprises a plurality of semiconductor layers having an energy bandgap wider than an energy bandgap of the first well layer (W1), wherein at least two layers of the plurality of semiconductor layers which is adjacent to the first and second well layers (W1, W2) have aluminum, Al, contents greater than that of the other layer
Data Source
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AI summary
Disclosed are a light emitting device, a light emitting device package and a lighting system. The light emitting device includes a first conductive semiconductor layer; a second conductive semiconductor layer on the first conductive semiconductor layer; and an active layer between the first and second conductive semiconductor layers, the active layer including a plurality of well layers and a plurality of barrier layers, wherein the well layers include a first well layer and a second well layer adjacent to the first well layer, the barrier layers include a first barrier layer disposed between the first and second well layers, the first barrier layer includes a plurality of semiconductor layers having an energy bandgap wider than an energy bandgap of the first well layer, and at least two layers of the plurality of semiconductor layers which is adjacent to the first and second well layers have aluminum contents greater than that of the other layer.