UVC-LED Segmented Electron Blocking Layer
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Solution Overview
Problem
In ultraviolet C light-emitting diodes (UVC-LEDs), the doping of beryllium, magnesium, or zinc in the electron blocking layer leads to difficulties in achieving optimal magnesium concentration, resulting in excessive impurities and defects that decrease luminous efficiency and cause unnecessary defect illumination.
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 with varying magnesium concentrations, where the second electron blocking layer has a magnesium concentration greater than 10^18 atoms/cm^3, and a two-dimensional hole gas (2DHG) inducing layer to control carrier injection and suppress electron overflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the doping amount of beryllium, magnesium or zinc, etc. is increased in the electron blocking layer, then the electron hole concentration and luminous efficiency are improved, but the memory effect and diffusion into the quantum well or quantum barrier occur, causing defects and decreasing luminous efficiency
Solution Approach 1:
The electron blocking layer is divided into multiple 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 diffusion into the quantum well, while the second electron blocking layer has a higher magnesium concentration (1×10^19 to 1×10^20 atoms/cm³) to effectively block electrons and improve luminous efficiency. This segmentation allows each layer to perform its specific function without causing harmful diffusion effects.
Solution Approach 2:
Different regions of the electron blocking layer are assigned different magnesium doping concentrations based on their specific functional requirements. The first electron blocking layer adjacent to the quantum well uses lower magnesium concentration to minimize diffusion risk, while the second electron blocking layer further from the quantum well uses higher magnesium concentration for superior electron blocking performance. This local quality variation optimizes both prevention of defect formation and enhancement of luminous efficiency.
2Reliability
If the aluminum concentration in the electron blocking layer is greater than the aluminum concentration in the quantum barrier, then the electron blocking capability is enhanced, but the doping of beryllium, magnesium or zinc, etc. becomes difficult
Solution Approach 1:
The electron blocking function is segmented across two separate layers with different aluminum and magnesium concentration configurations. The first electron blocking layer has lower aluminum concentration (making magnesium doping easier) while the second electron blocking layer has higher aluminum concentration (providing stronger electron blocking). This segmentation allows each layer to be optimized for its specific purpose without the trade-off present in a single high-aluminum layer.
Solution Approach 2:
The aluminum and magnesium concentration parameters are varied across different electron blocking layers to achieve both easy doping and effective electron blocking. By changing the aluminum concentration parameter from lower in the first layer to higher in the second layer, the patent simultaneously optimizes doping feasibility and electron blocking capability without the contradictions inherent in uniform high-aluminum structures.
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 effectively suppresses electron overflow, improves carrier injection efficiency, and enhances luminous efficiency by reducing defect illumination, resulting in improved light output power.
Implementation Method 1
a two-dimensional hole gas (2DHG) inducing layer to control carrier injection and suppress electron overflow
Implementation Method 2
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 including an n-type semiconductor layer, a p-type semiconductor layer, an active layer, a two-dimensional hole gas (2DHG) inducing layer, and an electron blocking layer is provided. The active layer is disposed between the n-type semiconductor layer and the p-type semiconductor layer, wherein a wavelength of a maximum peak of a spectrum emitted by the active layer ranges from 230 nm to 280 nm. The two-dimensional hole gas (2DHG) inducing layer is disposed between the active layer and the p-type semiconductor layer. A concentration of magnesium in the 2DHG inducing layer is less than 1017 atoms/cm3. The electron blocking layer is disposed between the p-type semiconductor layer and the 2DHG inducing layer. A concentration of magnesium in a part of the electron blocking layer adjacent to the 2DHG inducing layer is greater than 1019 atoms/cm3.