Abstract: A low-cost and low-power polyaniline-based (PANI) gas sensor is provided. The PANI-based gas sensor is formed on a flexible polyimide (PI) substrate using additive manufacturing techniques. The gas sensor can include silver interdigitated electrode (IDE) arrays and conducting polymeric sensing films (i.e., PANI) that are printed onto the PI substrate using a direct-write technology of aerosol-jet printing. Aerosol-jet printing enables high-resolution, non-contact deposition of both the electrode and chemically sensitive materials. The gas sensor is optionally capable of 5 ppm sensitivity and a sub-ppm detection limit.

Abstract: A structural health monitoring method is provided that utilizes self-sensing printed polymer structures. The method is based on resistivity properties of conductive materials, which can be integrated to a 3D printed polymer structure during additive manufacturing. An article to be monitored has at least one 3D printed polymer structure including a circuit comprising at least one conductive pathway extending through a non-conductive material. The resistance across the circuit is measured during or after loading of the article to determine a resistance value. The measured resistance value is compared to a known resistance value, and based on the comparison, a defect can be detected in the 3D printed polymer structure. Structural health monitoring systems and articles with integrated structural health monitoring are also provided.

Abstract: A system and method (referred to as a method) to fabricate sensors and electronic circuits. The method prints a first thin-film having an electronic conductivity of about less than a millionth of a Siemens per meter and a permalloy directly onto the first thin-film. The permalloy has a magnetic permeability greater than a predetermined level and has a thickness within a range of about 1 to 20 microns. The system prints a second thin-film directly onto the permalloy to encapsulate the permalloy onto the first thin-film and prints conductive traces directly onto the surfaces of the first-thin-film, the permalloy, and the second thin-film. In some applications, a sensor is packaged in an additively manufactured three-dimensional cylindrical shape that can be mounted on or is a unitary part of a current carrying conductor without incising, sharing, or severing (e.g., cutting) the current carrying conductor or its insulation.

Abstract: A structural health monitoring method is provided that utilizes self-sensing printed polymer structures. The method is based on resistivity properties of conductive materials, which can be integrated to a 3D printed polymer structure during additive manufacturing. An article to be monitored has at least one 3D printed polymer structure including a circuit comprising at least one conductive pathway extending through a non-conductive material. The resistance across the circuit is measured during or after loading of the article to determine a resistance value. The measured resistance value is compared to a known resistance value, and based on the comparison, a defect can be detected in the 3D printed polymer structure. Structural health monitoring systems and articles with integrated structural health monitoring are also provided.

Abstract: A system and method (referred to as a method) to fabricate sensors and electronic circuits. The method prints a first thin-film having an electronic conductivity of about less than a millionth of a Siemens per meter and a permalloy directly onto the first thin-film. The permalloy has a magnetic permeability greater than a predetermined level and has a thickness within a range of about 1 to 20 microns. The system prints a second thin-film directly onto the permalloy to encapsulate the permalloy onto the first thin-film and prints conductive traces directly onto the surfaces of the first-thin-film, the permalloy, and the second thin-film. In some applications, a sensor is packaged in an additively manufactured three-dimensional cylindrical shape that can be mounted on or is a unitary part of a current carrying conductor without incising, sharing, or severing (e.g., cutting) the current carrying conductor or its insulation.

Abstract: A method for producing metal chalcogenide nanoparticles, the method comprising: (i) producing hydrogen chalcogenide-containing vapor from a microbial source, wherein said microbial source comprises: (a) chalcogen-reducing microbes capable of producing hydrogen chalcogenide vapor from a chalcogen-containing source; (b) a culture medium suitable for sustaining said chalcogen-reducing microbes; (c) at least one chalcogen-containing compound that can be converted to hydrogen chalcogenide vapor by said chalcogen-reducing microbes; and (d) at least one nutritive compound that provides donatable electrons to said chalcogen-reducing microbes during consumption of the nutritive compound by said chalcogen-reducing microbes; and (ii) directing said hydrogen chalcogenide-containing vapor into a metal-containing solution comprising a metal salt dissolved in a solvent to produce metal chalcogenide nanoparticles in said solution, wherein said chalcogen is sulfur or selenium, and said chalcogenide is sulfide or selenide, res

Abstract: A method for producing metal chalcogenide nanoparticles, the method comprising: (i) producing hydrogen chalcogenide-containing vapor from a microbial source, wherein said microbial source comprises: (a) chalcogen-reducing microbes capable of producing hydrogen chalcogenide vapor from a chalcogen-containing source; (b) a culture medium suitable for sustaining said chalcogen-reducing microbes; (c) at least one chalcogen-containing compound that can be converted to hydrogen chalcogenide vapor by said chalcogen-reducing microbes; and (d) at least one nutritive compound that provides donatable electrons to said chalcogen-reducing microbes during consumption of the nutritive compound by said chalcogen-reducing microbes; and (ii) directing said hydrogen chalcogenide-containing vapor into a metal-containing solution comprising a metal salt dissolved in a solvent to produce metal chalcogenide nanoparticles in said solution, wherein said chalcogen is sulfur or selenium, and said chalcogenide is sulfide or selenide, res

Abstract: A wireless sensor platform and methods of manufacture are provided. The platform involves providing a plurality of wireless sensors, where each of the sensors is fabricated on flexible substrates using printing techniques and low temperature curing. Each of the sensors can include planar sensor elements and planar antennas defined using the printing and curing. Further, each of the sensors can include a communications system configured to encode the data from the sensors into a spread spectrum code sequence that is transmitted to a central computer(s) for use in monitoring an area associated with the sensors.

Abstract: A wireless sensor platform and methods of manufacture are provided. The platform involves providing a plurality of wireless sensors, where each of the sensors is fabricated on flexible substrates using printing techniques and low temperature curing. Each of the sensors can include planar sensor elements and planar antennas defined using the printing and curing. Further, each of the sensors can include a communications system configured to encode the data from the sensors into a spread spectrum code sequence that is transmitted to a central computer(s) for use in monitoring an area associated with the sensors.

Abstract: A method is disclosed for processing an insulator material or a semiconductor material. The method includes pulsing a plasma lamp onto the material to diffuse a doping substance into the material, to activate the doping substance in the material or to metallize a large area region of the material. The method may further include pulsing a laser onto a selected region of the material to diffuse a doping substance into the material, to activate the doping substance in the material or to metallize a selected region of the material.

Abstract: A composite Pt/Ti/WSi/Ni Ohmic contact has been fabricated by a physical deposition process which uses electron beam evaporation and dc-sputter deposition. The Ni based composite Ohmic contact on n-Sic is rapid thermally annealed (RTA) at 950° C. to 1000° C. for 30 s to provide excellent current-voltage characteristics, an abrupt, void free contact-SiC interface, retention of the as-deposited contact layer width, smooth surface morphology and an absence of residual carbon within the contact layer and/or at the Ohmic contact-SiC interface. The annealed produced Ni2Si interfacial phase is responsible for the superior electrical integrity of the Ohmic contact to n-SiC. The effects of contact delamination due to stress associated with interfacial voiding has been eliminated. Wire bonding failure, non-uniform current flow and SiC polytype alteration due to extreme surface roughness have also been abolished.

Abstract: This invention is directed to pure and modified Ta2O5 thin films deposited on suitable substrate and methods for making these Ta2O5 thin films. These Ta2O5 thin films exhibit superior properties for microwave communication, dynamic random access memory and integrated electronic applications. The Ta2O5 thin films perform well in these types of technologies due to the Ta 2O5 thin film component which allows for high dielectric constants, low dielectric loss, and good temperature and frequency stability, thus making them particularly useful in high frequency microwave applications.

Abstract: This invention is directed to pure and modified Ta2O5 thin films deposited on suitable substrates and methods for making these Ta2O5 thin films. These Ta2O5 thin films exhibit superior properties for microwave communication, dynamic random access memory and integrated electronic applications. The Ta2O5 thin films perform well in these types of technologies due to the Ta2O5 thin film component which allows for high dielectric constants, low dielectric loss, and good temperature and frequency stability, thus making them particularly useful in high frequency microwave applications.

Abstract: A composite Pt/Ti/WSi/Ni Ohmic contact has been fabricated by a physical deposition process which uses electron beam evaporation and dc-sputter deposition. The Ni based composite Ohmic contact on n-SiC is rapid thermally annealed (RTA) at 950° C. to 1000° C. for 30s to provide excellent current-voltage characteristics, an abrupt, void free contact-SiC interface, retention of the as-deposited contact layer width, smooth surface morphology and an absence of residual carbon within the contact layer and/or at the Ohmic contact-SiC interface. The annealed produced Ni2Si interfacial phase is responsible for the superior electrical integrity of the Ohmic contact to n-SiC. The effects of contact delamination due to stress associated with interfacial voiding has been eliminated. Wire bonding failure, non-uniform current flow and SiC polytype alteration due to extreme surface roughness have also been abolished.

Abstract: This invention is directed to pure and modified Ta2O5 thin films deposited on suitable substrates and methods for making these Ta2O5 thin films. These Ta2O5 thin films exhibit superior properties for microwave communication, dynamic random access memory and integrated electronic applications. The Ta2O5 thin films perform well in these types of technologies due to the Ta2O5 thin film component which allows for high dielectric constants, low dielectric loss, and good temperature and frequency stability, thus making them particularly useful in high frequency microwave applications.

Abstract: Thin films of ferroelectric composite material comprising barium strontium titanate (BSTO) combined with magnesium oxide additive are produced by metalorganic decomposition. The barium strontium titanate magnesium oxide ferroelectric composite comprises Ba.sub.1-x Sr.sub.x TiO.sub.3 /MgO, wherein x is greater than 0.0 but less than or equal to 0.75 and preferably is 0.4, and wherein the weight ratio of BSTO to magnesium oxide may range from 99 to 40 weight percent BSTO to 1 to 60 weight percent magnesium oxide. These films have desirable electronic properties and may have application to both active microwave and dynamic random access memory devices, including low dielectric constant, low loss factor, high tunability, and high resistivity. The films produced are uniformly thick and impurity free, with thicknesses of only 0.4 microns.