United States of America As Represented by the Administrator of Nasa

The United States of America As Represented by the Administrator of the

Other

Gary W Hunter

Jennifer C Xu

Dorothy Lukco

Azlin M Biaggi-Labiosa

Philip G Neudeck

Chung-Chiun Liu

John Zhang

Chung Chiun Liu

Robert L Leeper

Laura J Evans

Michael H Kulis

Gordon M Berger

Timothy J Palinski

Randall L Vander Wal

Benjamin J Ward

A tunable colorimetric sensor/optical filter is based on a lithography-free, asymmetric Fabry-Perot cavity. The sensor has a thin-film structure formed by a lossy, porous nanoplasmonic top film deposited on an actively tunable spacer middle layer, and a reflective base layer (either a metal or semiconductor). The structure is fabricated using wafer-scale PVD processes, and the middle layer responds to the presence of a stimulus in the local environment, by expanding in thickness resulting in a shift in resonance wavelength and thus an obvious change in color of the sensor, which color change is detectable by the naked-eye. Such layered geometries exhibit vibrant, macroscopic structural coloration owing to the broadband optical absorption of the top film, enabling the change in spacer thickness to be transduced visually, circumventing the need for sophisticated optical equipment for signal readout to observe the presence of the environmental stimulus.

Large-area, actively tunable, asymmetric Fabry-Perot cavities for colorimetric sensing and optical switching

A microsensor and its method of manufacture are disclosed based on templated metal or metal oxide nanostructures. The microsensor includes an electrode that in one embodiment may be configured as a first sawtooth patterned electrode having a series of first peaks and first valleys and a second electrode that by be configured as a second sawtooth patterned electrode having a series of second peaks and second valleys where the second peaks generally align with the first peaks of the first electrode. A plurality of templated metal or metal oxide nanostructures connect on one side to the first electrode and on another side to the second electrode, where an electrical property of the microsensor changes in response to exposure to an environment to be monitored.

Templated nanostructure sensors and methods of manufacture

Systems, methods, and other embodiments associated with gas detecting sensors. According to one embodiment, a gas sensor includes a metal layer, a barrier interlayer, a substrate layer, a first insulating layer, a conduction path, a contact pad, and a second insulating layer. The conduction path connects the metal layer to the contact pad. The second insulating layer prevents diffusion through the contact pad, the conduction path, or the metal layer. The sensor includes a wire bonded electrical connection to the contact pad such that voltage can be determined and/or applied.

Gas sensors with contact pads

A polymer electrolyte-based sensor is disclosed. The sensor includes a conductive polymer electrolyte film including water-retaining components. The water-retaining components facilitate operational conductivity of the conductive polymer electrolyte film in lower humidity environments than would be possible without the water-retaining components.

Polymer electrolyte-based sensors

Systems and methods that incorporate nanostructures into microdevices are discussed herein. These systems and methods can allow for standard microfabrication techniques to be extended to the field of nanotechnology. Sensors incorporating nanostructures can be fabricated as described herein, and can be used to reliably detect a range of gases with high response.

Processing of nanostructured devices using microfabrication techniques

A gas sensor comprises a substrate layer; a pair of interdigitated metal electrodes, said electrodes include upper surfaces, the electrodes selected from the group consisting of Pt, Pd, Au, Ir, Ag, Ru, Rh, In, Os, and their alloys. A first layer of solid electrolyte staying in between electrode fingers and partially on said upper surfaces of said electrodes, said first layer selected from NASICON, LISICON, KSICON and &#x3b2;&#x2033;-Alumina. A second layer of metal carbonate(s) as an auxiliary electrolyte engaging said upper surfaces of the electrodes and the first solid electrolyte. The metal carbonates selected from the group consisting of the following ions Na, K, Li, Ag, H, Pb, Sr, Ba, and any combination thereof. An extra layer of metal oxide selected from the group consisting of SnO, InO, TiO, WO, ZnO, FeO, ITO, CdO, UO, TaO, BaO, MoO, MoO, VO, NbO, CuO, CrO, LaO, RuO, RuO, ReO, ReO, AgO, CoO, CuO, SnO, NiO, PrO, BaO, PdO, HfO, HfOor other metal oxide and their mixtures residing above and in engagement with the second electrolyte to improve sensor performance and/or to reduce sensor heating power consumption.

Carbon dioxide gas sensors and method of manufacturing and using same

A gas sensor includes a substrate and a pair of interdigitated metal electrodes selected from the group consisting of Pt, Pd, Au, Ir, Ag, Ru, Rh, In, and Os. The electrodes each include an upper surface. A first solid electrolyte resides between the interdigitated electrodes and partially engages the upper surfaces of the electrodes. The first solid electrolyte is selected from the group consisting of NASICON, LISICON, KSICON, and &#x3b2;&#x2033;-Alumina (beta prime-prime alumina in which when prepared as an electrolyte is complexed with a mobile ion selected from the group consisting of Na, K, Li, Ag, H, Pb, Sror Ba). A second electrolyte partially engages the upper surfaces of the electrodes and engages the first solid electrolyte in at least one point. The second electrolyte is selected from the group of compounds consisting of Na, K, Li, Ag, H, Pb, Sror Baions or combinations thereof.

A miniaturized Schottky diode hydrogen and hydrocarbon sensor and the method of making same is disclosed and claimed. The sensor comprises a catalytic metal layer, such as palladium, a silicon carbide substrate layer and a thin barrier layer in between the catalytic and substrate layers made of palladium oxide (PdO). This highly stable device provides sensitive gas detection at temperatures ranging from at least 450 to 600&#xb0; C. The barrier layer prevents reactions between the catalytic metal layer and the substrate layer. Conventional semiconductor fabrication techniques are used to fabricate the small-sized sensors. The use of a thicker palladium oxide barrier layer for other semiconductor structures such as a capacitor and transistor structures is also disclosed.

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Gas sensor devices are provided having an atomically flat silicon carbide top surface that, in turn, provides for a uniform, and reproducible surface thereof.

Gas sensors using SiC semiconductors and method of fabrication thereof

A diode for sensing hydrogen and hydrocarbons and the process for manufacturing the diode are disclosed. The diode is a Schottky diode which has a palladium chrome contact on the C-face of an n-type 6H Silicon carbide epilayer. The epilayer is grown on the C-face of a 6H silicon carbide substrate. The diode is capable of measuring low concentrations of hydrogen and hydrocarbons at high temperatures, for example, 800&deg; C. The diode is both sensitive and stable at elevated temperatures.

Gas sensing diode comprising SiC

A diode for sensing hydrogen and hydrocarbons and the process for manufacturing the diode are disclosed. The diode is a Schottky diode which has a palladium chrome contact on the C-face of an n-type 6H Silicon carbide epilayer. The epilayer is grown on the C-face of a 6H silicon carbide substrate. The diode is capable of measuring low concentrations of hydrogen and hydrocarbons at high temperatures, for example, 800.degree. C. The diode is both sensitive and stable at elevated temperatures.

Gas sensing diode and method of manufacturing

A hydrogen sensitive metal alloy contains palladium and titanium to provide a larger change in electrical resistance when exposed to the presence of hydrogen. The alloy is deposited on a substrate and a thin film and connected across electrical circuitry to provide a sensor device that can be used for improved sensitivity and accuracy of hydrogen detection.

Growing community of inventors

Oberlin, OH, United States of America

Gary W Hunter