Dual Electron Blocking Layer UVC-LED Structure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In ultraviolet C light-emitting diodes (UVC-LEDs), doping the electron blocking layer with beryllium, magnesium, or zinc can lead to excessive impurities and defects due to diffusion into the quantum well or barrier, reducing luminous efficiency and causing unnecessary defect illumination, especially when the aluminum concentration in the electron blocking layer exceeds that in the quantum barrier.
Innovation Solution
The UVC-LED structure includes a specific configuration with an n-type and p-type semiconductor layer, an active layer, and two electron blocking layers, where the second electron blocking layer has a higher magnesium concentration (>1018 atoms/cm3) than the first, effectively suppressing electron overflow and improving hole carrier injection efficiency by controlling magnesium doping and aluminum molar fractions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electron blocking layer is doped with beryllium, magnesium or zinc to form a p-type semiconductor, then the electron hole concentration increases and luminous efficiency is improved, but excessive doping causes memory effect and diffusion into the quantum well or quantum barrier, forming defects and reducing luminous efficiency
Solution Approach 1:
The patent applies local quality by creating two distinct electron blocking layers with different magnesium doping concentrations. The first electron blocking layer has a lower magnesium concentration (1×10^18 to 1×10^19 atoms/cm³) to prevent excessive diffusion, while the second electron blocking layer has a higher magnesium concentration (1×10^19 to 1×10^20 atoms/cm³) to provide strong electron blocking capability. This spatial variation in doping concentration optimizes both electron blocking performance and prevention of defect formation.
Solution Approach 2:
The patent changes the doping concentration parameter by implementing a gradient structure where magnesium concentration varies across different layers. Specifically, the first electron blocking layer uses 1×10^18 to 1×10^19 atoms/cm³ while the second uses 1×10^19 to 1×10^20 atoms/cm³. This parameter optimization balances the need for high electron blocking efficiency with the need to prevent magnesium diffusion into the active layer that would cause defects.
2Reliability
If the aluminum concentration in the electron blocking layer is greater than in the quantum barrier, then the electron blocking capability is enhanced, but it becomes difficult to dope beryllium, magnesium or zinc into the electron blocking layer
Solution Approach 1:
The patent applies local quality by differentiating the aluminum concentration between the two electron blocking layers. The first electron blocking layer has a lower aluminum concentration (40% to 60%) that facilitates doping, while the second electron blocking layer has a higher aluminum concentration (60% to 80%) that provides superior electron blocking capability. This local differentiation resolves the contradiction between doping ease and blocking effectiveness.
Solution Approach 2:
The patent segments the electron blocking function into two separate layers with different material compositions. The first layer (AlGaN with 40%-60% Al) is optimized for doping ease, while the second layer (AlGaN with 60%-80% Al) is optimized for electron blocking performance. This segmentation allows each layer to be independently optimized for its specific function, resolving the contradiction between manufacturability and performance.
3Quantity of substance
If the doping amount of beryllium, magnesium or zinc is increased to improve electron hole concentration, then the luminous efficiency increases, but the memory effect and diffusion into the quantum well or quantum barrier increase, causing excessive impurities and defects
Solution Approach 1:
The patent segments the doping function by placing magnesium in two separate electron blocking layers with different concentration ranges. The first layer contains 1×10^18 to 1×10^19 atoms/cm³ magnesium that provides moderate electron hole concentration without excessive diffusion, while the second layer contains 1×10^19 to 1×10^20 atoms/cm³ magnesium that provides strong electron blocking. This segmentation prevents the memory effect and diffusion problems associated with high single-layer doping.
Solution Approach 2:
The first electron blocking layer acts as an intermediary between the magnesium-rich second electron blocking layer and the active layer. It provides a transition zone with moderate magnesium concentration that prevents direct diffusion of high concentrations of magnesium into the quantum well, thereby reducing defect formation while maintaining electron hole concentration.
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 the luminous efficiency of UVC-LEDs by preventing electron overflow and reducing defect illumination, resulting in improved device performance and increased light output power.
Implementation Method 1
The first electron blocking layer and the second electron blocking layer are located between the p-type semiconductor layer and the active layer, the concentration of magnesium in the second electron blocking layer is greater than the concentration of magnesium in the first electron blocking layer, and the concentration of magnesium in the second electron blocking layer is greater than 10^18 atoms/cm³
Implementation Method 2
In order to make an electron hole carrier to be easily injected into a light-emitting layer, active layer or multiple-quantum well (MQW), an electron blocking layer (EBL) in an ultraviolet C light-emitting diode (UVC-LED) structure is doped with beryllium, magnesium or zinc, etc. to form a p-type semiconductor
Implementation Method 3
The active layer is located between the n-type semiconductor layer and the p-type semiconductor layer, and the wavelength of the maximum peak of the spectrum emitted by the active layer ranges from 230 nm to 280 nm
Data Source
AI summary
An ultraviolet C light-emitting diode includes an n-type semiconductor layer, a p-type semiconductor layer, an active layer, a first electron blocking layer, and a second electron blocking layer. The active layer is disposed between the n-type semiconductor layer and the p-type semiconductor layer. The wavelength of the maximum peak of the spectrum emitted by the active layer ranges from 230 nanometers to 280 nanometers. The concentration of magnesium in the active layer is less than 1017 atoms/cm3. The first electron blocking layer and the second electron blocking layer are disposed between the p-type semiconductor layer and the active layer. The concentration of magnesium in the second electron blocking layer is greater than that of the first electron blocking layer and is greater than 1018 atoms/cm3.