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Project Topic
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Gas sensing technologies for carbon dioxide (CO2), carbon monoxide (CO), ethanol and hydrocarbons are important for many of applications such as air quality monitoring and realizing ventilation-on-demand strategies in air-conditioning systems, medical applications, industrial safety systems, aeronautic and automotive applications, breath-based alcohol sensing, and environmental monitoring, including sensors for integration in mobile phones. However, for many of these applications existing gas sensors are too expensive, bulky or low-performance. Thus, there is a critical need for gas sensor systems that are low-cost, compact, highly sensitive and specific to the targeted gas. To address this need, we will develop highly integrated waveguide-based optical gas sensor systems utilizing mid-infrared (mid-IR) graphene photodetectors targeting the wavelength range from 2 to 5 μm. Existing mid-IR detectors are typically based on compound semiconductors, which cannot be easily integrated with silicon photonics, thus precluding the development of low-cost optical gas sensors. The purpose of this project is to fill the current technology gap and demonstrate that nondispersive infrared (NDIR) gas sensor systems can be realized by utilizing mid-IR graphene detectors that are integrated with silicon photonic waveguide circuits. The proposed NDIR gas sensor system consists of a broadband IR emitter that couples light to a mid-IR spiral waveguide, which is exposed to the target gas. Thereby, certain wavelength bands of the light are absorbed by the presence of gas molecules while the light travels through the waveguide. The intensity of the signal at the end of the waveguide correlates with high sensitivity and specificity with the concentration of the targeted gas, which is detected by a mid-IR graphene detector (the target wavelength for CO2 sensing is 4.23 μm). Securing the realization of waveguide-based NDIR gas sensor systems is vital for sustaining the competitiveness of SenseAir, the world market leader for optical CO2 gas sensors, and to pave its way into the emerging multi-gas sensor market. With the emerging automotive air-conditioning market in sight, and the billion-unit-per-year smartphone market in mind, international competitors are already on their way to the same goal. To meet this challenge, we have assembled a world-class team, combining the gas-sensor experts at SenseAir with experts from academia in the areas of silicon photonic devices (KTH), graphene 3D integration (AMO, KTH), graphene production (AMO) and graphene modelling (ICN2). With an early entry into the graphene-based IR detector market, Europe can secure key intellectual property vital to future graphene-based ventures. The proposed project perfectly aligns with the strategic roadmap of the Graphene Flagship consortium and complements the Flagship Core Project, in which gas sensors are identified as an important objective for pushing European industrial competitiveness.
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