UV LED Second Conductive Layer for Carrier Injection
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Solution Overview
Problem
Conventional ultraviolet light-emitting devices face issues with reduced luminous efficiency due to non-uniform carrier injection and lower indium composition in quantum wells, leading to decreased luminous intensity and electron blocking efficiency.
Innovation Solution
Incorporating a second conductive-type semiconductor layer with a p-type Alx1Ga1-x1N layer and a p-type InyAlx2Ga1-y-x2N layer between the active layer and the electron blocking layer, which reduces pit density and improves crystallinity, thereby enhancing electron blocking efficiency and luminous intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional light-emitting device structure is used, then the device can be manufactured with standard processes, but the luminous efficiency is reduced due to non-uniform carrier injection and pit formation
Solution Approach 1:
The patent introduces a second conductive-type second semiconductor layer as an intermediary layer between the active layer and the electron blocking layer. This intermediate layer mediates the carrier injection process, improving uniformity and reducing pit formation, thereby resolving the contradiction between standard manufacturing and luminous efficiency.
Solution Approach 2:
The patent employs a composite semiconductor structure with multiple layers having different compositions and conductive types. The combination of the second conductive-type second semiconductor layer with specific composition ratios creates a composite structure that optimizes carrier injection while maintaining manufacturability.
2Illumination intensity
If the amount of injected current is increased to improve luminous intensity, then the luminous intensity increases, but the luminous efficiency is lowered due to the droop problem
Solution Approach 1:
The patent optimizes the composition ratios of the semiconductor layers, particularly the second conductive-type second semiconductor layer, to adjust carrier injection parameters. This allows achieving high luminous intensity while maintaining efficiency by improving carrier distribution uniformity across quantum wells.
Solution Approach 2:
The patent creates local quality variations through the multi-layer structure with different conductive types and compositions. The second conductive-type second semiconductor layer provides localized carrier injection enhancement, ensuring uniform carrier distribution across different regions of the active layer, thereby preventing efficiency droop at high current levels.
3Loss of energy
If the composition of indium in quantum well is increased to improve luminous efficiency, then the luminous efficiency improves, but the device becomes more difficult to manufacture with standard processes
Solution Approach 1:
The patent segments the indium-containing quantum well structure into multiple layers with optimized individual compositions. The second conductive-type second semiconductor layer is divided into sub-layers with graded composition ratios, making the overall high-indium structure manufacturable through standard processes while maintaining high luminous 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
The solution effectively improves luminous efficiency, maintains operating voltage, and maintains wavelength, resulting in increased luminous intensity and improved electron blocking efficiency.
Implementation Method 1
an electron blocking layer disposed between the active layer and the second conductive-type first semiconductor layer; and a second conductive-type second semiconductor layer disposed between the last quantum barrier of the active layer and the electron blocking layer
Implementation Method 2
A light-emitting device or light emitting diode includes a p-n junction diode having a property of converting electric energy into light energy
Implementation Method 3
The ultraviolet light-emitting device (UV LED) is a light-emitting device emitting light in a wavelength range of 200 nm to 400 nm
Data Source
AI summary
An embodiment relates to an ultraviolet light-emitting device, a method for manufacturing an ultraviolet light-emitting device, a light-emitting device package and an illumination apparatus. The ultraviolet light-emitting device includes a first conductive-type semiconductor layer; an active layer comprising a plurality of quantum walls and a plurality of quantum wells and disposed on the first conductive-type semiconductor layer; a second conductive-type first semiconductor layer disposed on the active layer; an electron blocking layer disposed between the active layer and the second conductive-type first semiconductor layer; and a second conductive-type second semiconductor layer disposed between the last quantum wall of the active layer and the electron blocking layer, wherein the second conductive-type second semiconductor layer includes a p-type Alx1Ga1-x1N layer (0≤x1≤1) and a p-type InyAlx2Ga1-y-x2N layer (0≤x2≤1, 0≤y≤1, 0≤x2+y≤1).