A single wire large-area filament emitter for spectroscopic ethanol gas sensing fabricated using a wire bonding tool

Non-dispersive infrared (NDIR) gas spectroscopy is a highly accurate optical gas sensing technology, which has been implemented in various industrial applications. However NDIR systems remain too expensive for many consumer and automotive apphcations. The cost of the infrared (IR) emitter component is a substantial part of the total system cost. In this paper we report of a single filament IR emitter that is fabricated using wire bonding technology. Our fabrication approach offers the prospect of a fully automated assembly by means of utihzing a wire bonding tool to integrate the single filament to the MEMS structured silicon substrate. An apphcation-specific wire bond trajectory enables the mechanical attachment of the filament to form the meander-shaped emitter with a total area of 1 mm2. The fabricated IR emitter utilizes a Kanthal (FeCrAl) filament with very high thermal stability and excellent emitting properties under atmospheric conditions. The packaged IR emitter has been characterized using Fourier transform infrared (FTIR) spectroscopy to study the emitted IR spectrum with respect to the requirements of NDIR systems.QC 20171211</p

Stopping a roller coaster train

A roller coaster ride comes to an end. Magnets on the train induce eddy currents in the braking fins, giving a smooth rise in braking force as the remaining kinetic energy is absorbed by the brakes and converted to thermal energy. In this paper an IR camera was used to monitor the temperature of the first braking fin, before, during and after the passage of a train. In addition, the resulting acceleration of the train was modelled and compared to accelerometer data for the Kanonen roller coaster in Liseberg. The results are used to model the distribution of temperature increase over the braking fins. Finally, the cooling of the fins after the passage of the train is analysed and compared to the IR data

Fabrication of an Infrared Emitter using a Generic Integration Platform Based on Wire Bonding

This paper reports a novel approach for the fabrication of infrared (IR)emitters for non-dispersive infrared gas sensing. The proposed concept enables theintegration of superior resistive heater materials with microelectromechanical systems(MEMS) structures. In this study, non-bondable filaments made of nickel chromium areattached to mechanical attachment structures using a fully automated state-of-the-artwire bonder. The formation of the electrical contacts between the integrated filamentsand the electrical contact pattern on the substrate is performed using conventionalgold stud bumping technology. The placement accuracy of the integrated filamentsis evaluated using white-light interferometry, while the contact formation using studbumping to embed the filaments is investigated using focus ion beam milled crosssections.A proof-of-concept IR emitter has been successfully operated and heated upto 960 C in continuous mode for 3 hours.QC 20161121</p

Compact Non-Dispersive Infrared Multi-Gas Sensing Platform for Large Scale Deployment with Sub-ppm Resolution

We report on a novel, cost-effective non-dispersive infrared (NDIR) multi-gas sensor aimed at environmental air pollution monitoring. The rugged design of the K96 sensor core combines highest compactness and low-power consumption with our unique multi-channel cell design, featuring the detection of up to three different gases simultaneously, including CO2, CH4, N2O, and H2O. Our sensing platform allows the selection of the target gases as well as the concentration ranges, thus providing highly customizable gas sensor systems targeting application-specific gas monitoring settings. The sensor core comes with an implemented calibration model, and can address in real time any cross-sensitivity between the NDIR gas-sensing channels. We provide an immensely versatile sensing system while ensuring high sensing stability combined with high precision (2 and N2O, 4). The K96 multi-gas sensor core offers a resilient sensor solution for the increasing demand of compact monitoring systems in the field of environmental monitoring at reasonable costs for medium-to-high volumes

Carbon Dioxide Sensing with Low-confinementHigh-sensitivity Mid-IR SiliconWaveguides

We present a low-confinement Si waveguide for 4.26 μm wavelength and applyit to sense CO2 concentrations down to 0.1 %. We demonstrate the highest reportedwaveguide sensitivity to CO2: 44% of the free-space sensitivity.QC 20190802</p

Carbon dioxide absorption spectroscopy with a mid-infrared silicon photonic waveguide

Carbon dioxide (CO2) is a gas vital for life on Earth. It is also a waste product of human activities and is widely used in agriculture and industry. Its accurate sensing is therefore of great interest. Optical sensors exploiting the mid-infrared light absorption of CO2 provide high selectivity, but their large size and high cost limit their use. In this Letter, we demonstrate CO2 gas sensing at 4.2 µm wavelength using an integrated silicon waveguide, featuring a sensitivity to CO2 of 44% that of free-space sensing. The suspended waveguide is fabricated on a silicon-on-insulator substrate by a single-lithography-step process, and we route it into a mid-infrared photonic circuit for on-chip-referenced gas measurements. Its demonstrated performance and its simple and scalable fabrication make our waveguide ideal for integration in miniaturized CO2 sensors for distributed environmental monitoring, personal safety, and medical and high-volume consumer applications

Graphene ribbons with suspended masses as transducers in ultra-small nanoelectromechanical accelerometers

Nanoelectromechanical system (NEMS) sensors and actuators could be of use in the development of next generation mobile, wearable, and implantable devices. However, these NEMS devices require transducers that are ultra-small, sensitive and can be fabricated at low cost. Here, we show that suspended double-layer graphene ribbons with attached silicon proof masses can be used as combined spring-mass and piezoresistive transducers. The transducers, which are realized using processes that are compatible with large-scale semiconductor manufacturing technologies, can yield NEMS accelerometers that occupy at least two orders of magnitude smaller die area than conventional state-of-the-art silicon accelerometers.Comment: 42 pages, 4 figure