Solar-Blind AlGaN Photodiode for UV-C Detection Without Sunlight Interference
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Solution Overview
Problem
Conventional solar blind sensors are limited by their high cost, susceptibility to interference from background radiation, and inability to detect wavelengths other than UV-C radiation, which restricts their application in environments requiring precise measurements or broader spectral range detection.
Innovation Solution
A solar blind photodetector device using a substrate with a defect-reducing nucleation layer and compositionally graded AlGaN materials, featuring an intrinsic light detecting region with a bandgap greater than 4.35 eV, designed to detect electromagnetic radiation below 285 nm with minimal interference from solar radiation, and capable of operating across a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photodetectors are used to detect sunlight, then they can detect a broad spectral range, but they suffer from interference from visible light and cannot achieve solar blind detection
Solution Approach 1:
The patent applies local quality by creating a photodetector with spatially varying properties: the aperture region has different optical characteristics than the detection region. The aperture is designed to be transparent to UV-C wavelengths while blocking visible light, and the detection region uses materials with specific bandgaps (4.35-4.7 eV) that respond only to UV-C. This localized differentiation of optical properties enables solar blind detection by allowing UV-C entry while blocking interfering visible light.
Solution Approach 2:
The patent employs parameter changes by selecting and optimizing specific material parameters: bandgap energy (4.35-4.7 eV), aperture transparency wavelength range (200-280 nm), and layer thicknesses. These parameter selections create a detector that is insensitive to visible light wavelengths while maintaining high sensitivity to UV-C, thereby achieving solar blind operation through precise parameter control.
2Measurement precision
If solar blind sensors are used to detect UV-C radiation, then they achieve high detection accuracy without sunlight interference, but they are more expensive to manufacture
Solution Approach 1:
The patent achieves universality by designing a multi-functional device structure that combines UV-C detection with visible light blocking in a single integrated photodetector. The aperture region serves dual purposes: it acts as an optical element for UV-C transmission while simultaneously functioning as a visible light filter. This multi-functionality reduces the need for separate components and simplifies the overall system, potentially lowering manufacturing costs.
Solution Approach 2:
The patent uses composite materials by combining different semiconductor layers with specific bandgap properties (AlGaN, GaN, InGaN) to create a heterostructure that detects UV-C while blocking visible light. The composite nature of these material layers enables precise spectral selectivity through material composition control rather than requiring expensive specialized materials, making the manufacturing process more accessible.
3Object-affected harmful factors
If photodetectors are designed to respond only to UV-C radiation, then they eliminate sunlight interference, but they cannot detect other wavelengths of light necessary for some applications
Solution Approach 1:
The patent applies segmentation by dividing the photodetector into functionally distinct regions: an aperture region optimized for UV-C transmission and visible light blocking, and a detection region with specific bandgap materials for UV-C sensitivity. This segmentation allows each region to be optimized for its specific function while working together as an integrated system, achieving solar blind detection without requiring the entire device to be uniformly designed for a single wavelength range.
4Adaptability or versatility
If conventional photodetectors are used in environments with background radiation, then they can detect multiple wavelengths, but they suffer from reduced measurement accuracy due to interference
Solution Approach 1:
The patent converts the harmful effect of background radiation into a beneficial filtering mechanism. The aperture region's optical properties are specifically designed to block visible light wavelengths that constitute background radiation, while simultaneously transmitting UV-C wavelengths. This transforms what would be interfering background radiation into a filtered signal, improving measurement accuracy by eliminating unwanted wavelengths while preserving the desired UV-C detection capability.
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 device achieves a high signal-to-noise ratio and efficient detection of UV-C radiation without interference from solar radiation, enabling cost reduction and expanded spectral range detection, suitable for applications like biotechnology and environmental monitoring.
Implementation Method 1
The aperture region is transparent to electromagnetic radiation ranging in wavelength from less than 280 nanometers
Implementation Method 2
an intrinsic light detecting region having a bandgap of larger than 4.35 eV... The intrinsic light detecting region comprises an aluminum gallium scandium nitride material
Data Source
AI summary
According to the present invention, techniques related generally to a photodiode device configured to be receptive to a near ultraviolet (UV-C) emission wavelength range. This wavelength range is specifically designed to be immune to background radiation produced by the Sun, rendering the communication device Solar Blind, and immune to other similar forms of interference. In particular, the present invention provides a light receiving and sensing system using various compositional Al, Ga, Sc, and N solid state materials to detect and measure radiation with a high degree of fidelity. This invention has numerous applications not only in detection and sensing technologies, but also measurement, communication, navigation, and other related aspects.