Plasmonic Schottky Photodetector Layout for Multiband Polarization Sensing
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Solution Overview
Problem
Current photodetectors face challenges in detecting multiple wavelength bands and polarizations efficiently, particularly in the ultraviolet, visible, and near-infrared spectra, due to their limited bandwidth and polarization selectivity, which hinders their application in advanced technologies like CMOS imaging and Li-Fi.
Innovation Solution
A two-electrode, single-device interdigitated grating-based Schottky plasmonic photodetector with metal-semiconductor-metal (MSM) structure is designed, where both electrodes are placed on the same surface, utilizing surface plasmons to enhance photocurrent and allow detection of multiple wavelength bands and polarizations by tuning the grating periodicity and polarization angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single photodetector device is used, then device complexity is reduced, but the ability to detect multiple wavelength bands and polarizations is limited
Solution Approach 1:
The patent implements multi-functionality by integrating multiple interdigitated gratings with different periodicities and orientations into a single photodetector device. Each grating structure is designed to detect specific wavelength bands and polarization states, enabling one device to perform multiple detection functions simultaneously across UV, visible, and near-infrared spectra without requiring separate devices for each function
Solution Approach 2:
The patent applies segmentation by dividing the photodetector surface into multiple distinct interdigitated grating regions, where each region has specific geometric parameters (periodicity, orientation) tailored to detect particular wavelength bands and polarizations. This segmentation allows independent optimization of each detection channel while maintaining a unified device structure
2Adaptability or versatility
If multiple separate photodetector devices are used to detect different wavelength bands and polarizations, then detection coverage is improved, but alignment complexity and device integration difficulty increase
Solution Approach 1:
The patent merges multiple detection functions into a single integrated photodetector device by fabricating multiple interdigitated grating structures on the same semiconductor substrate. This combining approach eliminates the need for separate devices and complex alignment procedures, as all grating structures are co-fabricated with precise relative positions and orientations during the same manufacturing process
3Ease of manufacture
If conventional photodetector design is used, then manufacturing simplicity is maintained, but bandwidth and polarization selectivity are limited
Solution Approach 1:
The patent employs parameter changes by systematically varying the geometric parameters of interdigitated gratings (periodicity, finger width, spacing, orientation angles) to tune the detection characteristics for different wavelength bands and polarization states. This allows customization of detection properties while maintaining compatibility with standard semiconductor fabrication processes
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 design enables the detection of multiple narrow bands of electromagnetic radiation across various spectra with improved polarization sensitivity, reducing the need for multiple devices and complex alignment processes, thus enhancing the photodetector's efficiency and versatility.
Implementation Method 1
the concentration of the electromagnetic near-field in the light sensing area by means of surface plasmons polaritons (SPP) defined as a dualism of light surface waves and collective electronic oscillations on the surface of metals
Implementation Method 2
photons absorbed in the metal near the interface (less than 40 nm) between metal and semiconductor may provide enough energy to a fraction of electrons ('hot' electrons located below or at the Fermi level of metal) and thus they may be able to surmount the Schottky barrier
Data Source
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AI summary
The present disclosure presents an innovative design concept for metal interdigitated grating-based metal-semiconductor-metal Schottky plasmonic photodetectors, able to detect multiband, multi-polarization electromagnetic radiation in the ultraviolet, visible, near and mid infrared spectrum by a using a single device with two electrodes which are both positioned on the same surface of semiconductor device, being thus a genuine planar semiconducting technology. The innovative concept shows that even if the surface plasmon enhanced photosensitive devices are wavelength and polarization-selective, it is possible to detect two and more narrow bands of the electromagnetic radiation with different polarizations by using a single-device two-electrode plasmonic Schottky photodetector where both metal contacts are placed on the device surface which is receiving the radiation. The novel design concept and associated fabrication technology will be presented by means of a generic metal-semiconductor-metal device, and specific examples will be then described.