A Miniaturised, Fully Integrated NDIR CO2 Sensor On-Chip

Sensors

卷:21

Joris Roels¹  Gunther Roelkens²  Xiaoning Jia²  Roel Baets² 

[1] Melexis Technologies NV, Transportstraat 1, 3980 Tessenderlo, Belgium;

[2] Photonics Research Group, INTEC, Ghent University-Imec, Technologiepark 126, 9052 Gent, Belgium;

关键词: optical sensor;    CO₂ sensor;    NDIR;    silicon photonics;   

DOI  :  10.3390/s21165347

来源: DOAJ

【 摘 要 】

In this paper, we present a fully integrated Non-dispersive Infrared (NDIR) CO₂ sensor implemented on a silicon chip. The sensor is based on an integrating cylinder with access waveguides. A mid-IR LED is used as the optical source, and two mid-IR photodiodes are used as detectors. The fully integrated sensor is formed by wafer bonding of two silicon substrates. The fabricated sensor was evaluated by performing a CO₂ concentration measurement, showing a limit of detection of ∼750 ppm. The cross-sensitivity of the sensor to water vapor was studied both experimentally and numerically. No notable water interference was observed in the experimental characterizations. Numerical simulations showed that the transmission change induced by water vapor absorption is much smaller than the detection limit of the sensor. A qualitative analysis on the long term stability of the sensor revealed that the long term stability of the sensor is subject to the temperature fluctuations in the laboratory. The use of relatively cheap LED and photodiodes bare chips, together with the wafer-level fabrication process of the sensor provides the potential for a low cost, highly miniaturized NDIR CO₂ sensor.

【 授权许可】

Unknown