Abstract
Nondispersive infrared (NDIR) spectroscopy is an important technology for highly accurate and maintenance-free sensing of gases, such as ethanol and carbon dioxide. However, NDIR spectroscopy systems are currently too expensive, e.g., for consumer and automotive applications, as the infrared (IR) emitter is a critical but costly component of these systems. Here, we report on a low-cost large-area IR emitter featuring a broadband emission spectrum suitable for small NDIR gas spectroscopy systems. The infrared emitter utilizes Joule heating of a Kanthal (FeCrAl) filament that is integrated in the base substrate using an automated high-speed wire bonding process, enabling simple and rapid formation of a long meander-shaped filament. We describe the critical infrared emitter characteristics, including the effective infrared emission spectrum, thermal frequency response, and power consumption. Finally, we integrate the emitter into a handheld breath alcohol analyzer and show its operation in both laboratory and real-world settings, thereby demonstrating the potential of the emitter for future low-cost optical gas sensor applications.
Highlights
Gas sensors are important for a variety of industrial applications, such as environmental monitoring and control of industrial processes[1,2]
Our approach can generate suspended geometries such as free-standing filaments that do not suffer from delamination problems during heating that can arise due to thermally induced mechanical stresses in conventional thin film-based MEMS emitters
The characterization of the emission spectrum of the IR emitter utilizing the time-resolved measurement mode showed that the emitted radiation has a maximum intensity at a wavelength of ≈4.8 μm, correlating well with the calculated black body emission spectrum when assuming an emissivity of oxidized Kanthal filaments of 0.7
Summary
Gas sensors are important for a variety of industrial applications, such as environmental monitoring and control of industrial processes[1,2]. NDIR sensor systems have been successfully commercialized and utilized in a variety of applications, for example, in monitoring chemical processes in industry, in heating, ventilation and air conditioning (HVAC) systems of buildings and Schröder et al Microsystems & Nanoengineering (2021)7:87 where the IR radiation propagates an extended distance through the sample gas and is partially absorbed by it. MEMS IR emitter designs can experience high thermally induced mechanical stresses due to the different coefficients of thermal expansion of the membrane material(s) and the emitting material(s), thereby increasing the risk of layer delamination. All of these factors can make MEMS IR emitters relatively costly
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
