Gas detector with hyperdoped SiC semiconductor material and related methods
Inventors
Sugrim, Chandraika • Kumar, Ranganathan • Kar, Aravinda • Burkhart, Robert
Assignees
US Department of Navy • University of Central Florida Research Foundation Inc
Publication Number
US-10732118-B2
Publication Date
2020-08-04
Expiration Date
2039-10-09
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Abstract
A detector is for identifying chemicals in a sample. The detector may include a photodetector comprising SiC semiconductor material and configured to have an acceptor energy band of range Ea−ΔEa to Ea+ΔEa. The SiC semiconductor material may be doped with a dopant to exceed a threshold dopant concentration level. The photodetector may be configured to receive fluorescence information from the sample.
Core Innovation
The invention relates to a detector for identifying chemicals in a sample, featuring a photodetector comprising silicon carbide (SiC) semiconductor material. This SiC material is doped with a dopant to exceed a threshold dopant concentration level, resulting in the formation of an acceptor energy band ranging from Ea−ΔEa to Ea+ΔEa. The photodetector is configured to receive fluorescence information emitted from the sample. By heavily doping the SiC material (hyperdoping), rather than lightly doping, the acceptor energy band broadens, enabling the detection of a wide variety of chemical compounds that emit photons within this energy range.
In addition to the photodetector, the detector may include a pump optical source that emits a pump optical signal with a known modulation into the sample. A tunable optical source emits a boosting optical signal at the photodetector, which can modify the acceptor energy band to detect multiple compounds in the sample simultaneously. The fluorescence information received by the photodetector carries the known modulation from the pump optical signal, which helps to increase signal-to-noise ratio by screening out background radiation.
The device further incorporates a probe optical source emitting a probe optical signal at the photodetector, and a probe photodetector that detects changes in this probe optical signal caused by the photodetector. A processor coupled to the probe photodetector bandpass filters its output to identify chemicals in the sample. The detector system can also employ a multi-core optical fiber to facilitate optical coupling between the photodetector, probe optical source, and probe photodetector. By analyzing phase shifts in the changed probe optical signal, the processor can determine the chemicals in the sample and their respective distances, allowing for three-dimensional modeling of the sample over time.
The background problem addressed is the need for a chemical sensing approach that is flexible in packaging demands and offers a robust feature set. Existing chemical detection applications, such as monitoring contaminants in air supply systems, benefit from a detector capable of identifying multiple chemical compounds flexibly and remotely. The invention tackles limitations of conventional detectors by introducing a tunable, hyperdoped SiC photodetector that provides broader detection capabilities, remote sensing functionality, and enhanced signal processing through modulated optical signals.
Claims Coverage
The patent includes multiple independent claims covering the detector device, a detector system, and a method of making the detector, each emphasizing key inventive features concerning the hyperdoped SiC photodetector, optical sources, and signal processing.
Photodetector comprising hyperdoped silicon carbide semiconductor material
A photodetector including silicon carbide semiconductor material doped with a dopant to exceed a threshold concentration level, resulting in an acceptor energy band of range Ea−ΔEa to Ea+ΔEa, configured to receive fluorescence information from a sample.
Detector with pump optical source and tunable optical source for multi-compound detection
A detector further comprising a pump optical source emitting a modulated pump optical signal into the sample, and a tunable optical source emitting a boosting optical signal at the photodetector, configured to change the acceptor energy band range to detect multiple compounds via fluorescence information having the known modulation.
Incorporation of probe optical source, probe photodetector, and processor for chemical identification
Adding a probe optical source emitting a probe optical signal at the photodetector, a probe photodetector detecting the changed probe optical signal, and a processor coupled to the probe photodetector configured to bandpass filter and identify chemicals in the sample.
Use of a multi-core optical fiber for optical coupling
A multi-core optical fiber comprising multiple cores optically coupled between the photodetector and the probe optical source and probe photodetector, enabling identification of chemicals and respective distances based on phase shift in the changed probe optical signal.
Detector system with directional device and three-dimensional chemical modeling
A detector system comprising a directional device coupled to the detector, where the detector includes a pump optical source with known modulation, phase, and angle of incidence; a hyperdoped SiC photodetector; a probe optical source; a probe photodetector; and a processor configured to identify chemicals and their distances and to provide a time-based three-dimensional model of the sample based on known positioning.
Method of making a detector with hyperdoped silicon carbide and integrated optical sources
Forming a photodetector comprising hyperdoped SiC semiconductor material with an acceptor energy band range, coupling a pump optical source emitting a modulated pump optical signal into the sample, coupling a tunable optical source for boosting signals and changing the energy band range, coupling a probe optical source and probe photodetector, and coupling a processor to bandpass filter and identify chemicals based on received signals.
Overall, the claims cover the invention of a hyperdoped SiC photodetector configured to receive modulated fluorescence signals, use of pump and tunable optical sources to detect multiple chemicals, utilization of probe optical sources and photodetectors for signal detection and filtering, optical coupling via multi-core fibers, integration in a directional system for spatial chemical mapping, and methods for fabricating and operating such detectors.
Stated Advantages
The detector provides remote sensing capability, allowing chemical detection without physical contact with the sensor.
Use of optical signals instead of electrical signals enables simpler, cost-effective fabrication without the need for electrical contacts or bias voltage, resulting in a wireless sensor with no 1/f noise.
Tunable detection capability allows sensing of multiple chemicals within a mixture without requiring separate detectors for each constituent.
The sensor can operate uncooled at room temperature due to the wide bandgap semiconductor material.
SiC material provides high resistance to harsh environments including high temperatures, high pressure, corrosion, oxidation, and radiation, making the sensor suitable for applications in nuclear reactors, submarines, space, and medical sensing owing to its biocompatibility.
Signal modulation and bandpass filtering improve signal-to-noise ratio, reducing false positives and increasing detectability of compound concentrations.
The detector can provide quantitative information such as compound concentration, volumetric extent, spatial location, and temporal changes including growth and migration of chemical clouds.
Documented Applications
Monitoring air quality in air supply systems within aircraft.
Remote sensing of chemicals in gas samples, fluid samples such as aqueous solutions, and solid compound samples.
Chemical detection in harsh environments such as high temperatures, pressures, radiation environments including nuclear power reactors, submarines, and space applications.
Medical sensor applications due to SiC's biocompatibility.
Providing time-based three-dimensional models of chemical samples, including tracking concentration changes, cloud growth, and migration by scanning spatial angles, distances, and time.
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