Nanohole array based sensors with various coating and temperature control
Inventors
Zhao, Yangyang • ZAGHLOUL, MONA • Semancik, Stephen • Benkstein, Kurt D.
Assignees
George Washington University • National Institute of Standards and Technology NIST • United States Department of Commerce
Publication Number
US-11035792-B2
Publication Date
2021-06-15
Expiration Date
2039-03-06
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Abstract
A nanohole array (NHA)-based plasmonic sensor (e.g., gas/condensed phase sensor), their preparation, and their use to detect and analyze samples, especially mixtures of chemicals/bio-chemicals.
Core Innovation
The invention relates to nanohole array (NHA)-based plasmonic sensors designed for detecting and analyzing samples including mixtures of chemicals and bio-chemicals. These sensors include a substrate partially covered with a deposit, a plasmonic layer on the deposit, and one or more functional layers on the plasmonic layer, with the sensor comprising a plurality of nanoholes. The functional layers can be porous absorptive materials or capture affinity layers such as metal organic frameworks (MOFs).
The problem addressed by the invention arises from the difficulty of detecting low concentrations of gas-phase analytes using conventional plasmonic platforms because poor adsorption over noble metals like gold hinders significant refractive index changes. This limits high-performance plasmonic gas sensors, particularly for sub μmol/mol analyte concentrations. There is a need for miniaturized room-temperature operable sensors with enhanced sensitivity that can detect low concentration gases for applications such as food safety, environmental monitoring, and disease diagnostics.
Claims Coverage
The patent contains several independent claims covering the nanohole array plasmonic sensor structure, the method of making the sensor, and the method of detecting analytes using the sensor, featuring multiple inventive elements.
Nanohole array plasmonic sensor structure with specific layer configurations and thicknesses
Claims describe a sensor comprising a substrate partially covered with a deposit; a plasmonic layer on the deposit; and one or more functional layers on the plasmonic layer. The sensor comprises a plurality of nanoholes. The functional layers have a thickness between about 5 nm and about 20 nm. The plasmonic layer can be gold, silver, copper, aluminum, platinum, or combinations. The substrate is etchable, preferably silicon, with the deposit including Si3N4 or SiO2. The sensor can have between 1 and about 20 functional layers and the nanoholes have diameters ranging from about 10 to about 500 nm with specific periods. Nanoparticles can further coat the nanohole arrays, and an integrated heater may be included.
Method of making the nanohole array plasmonic sensor with integrated heater and controlled structuring
The method includes depositing a covering on a substrate, patterning a nanohole array, depositing an insulation layer while leaving nanohole array areas uncovered, patterning a heater on the substrate, patterning a membrane window on the backside, etching the substrate to create a membrane, depositing a plasmonic layer centrally relative to the heater, and coating the plasmonic layer with one or more functional layers of thickness between about 5 nm and about 20 nm.
Method of detecting and analyzing gases or condensed phase samples using temperature-varied optical analysis
The method involves providing the nanohole sensor, contacting it with a gas or condensed/liquid sample, and optically analyzing the sample at one or more temperatures. The analysis may involve step-wise temperature changes and measuring intensity change at the peak wavelength, multiple wavelengths, or changes in color channels. The analysis can be performed using spectrometers or cameras.
The claims cover the nanosensor structure with specified materials and dimensions, a fabrication method incorporating heaters and membranes, and methods for analyte detection through temperature-controlled optical analysis, highlighting the sensor's configuration and functional versatility for gas and condensed phase sensing.
Stated Advantages
Detection of different samples with low limits of detection, including gases at part-per-billion levels.
Operational capability at various controlled temperatures enhancing discrimination and analysis of sample components.
Coating with combinations of materials allowing measurement of different gas analytes.
Adaptation for use with common optical devices such as cell phone cameras, providing a lower cost alternative to spectrometers.
Documented Applications
Detection and analysis of low concentration gases, including acetone and ethanol vapors, with relevance to food safety, environmental monitoring, and disease diagnostics such as diabetes.
Detection and analysis of condensed/liquid phase samples, including biomolecules such as DNA, proteins, and extracellular vesicles using biological functional coatings.
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