Detection of volatile organic compounds using mid-infrared silicon nitride waveguide sensors.
Sci Rep
; 12(1): 5572, 2022 04 02.
Article
in En
| MEDLINE
| ID: mdl-35368033
ABSTRACT
Mid-infrared (mid-IR) sensors consisting of silicon nitride (SiN) waveguides were designed and tested to detect volatile organic compounds (VOCs). SiN thin films, prepared by low-pressure chemical vapor deposition (LPCVD), have a broad mid-IR transparent region and a lower refractive index (nSiN = 2.0) than conventional materials such as Si (nSi = 3.4), which leads to a stronger evanescent wave and therefore higher sensitivity, as confirmed by a finite-difference eigenmode (FDE) calculation. Further, in-situ monitoring of three VOCs (acetone, ethanol, and isoprene) was experimentally demonstrated through characteristic absorption measurements at wavelengths λ = 3.0-3.6 µm. The SiN waveguide showed a five-fold sensitivity improvement over the Si waveguide due to its stronger evanescent field. To our knowledge, this is the first time SiN waveguides are used to perform on-chip mid-IR spectral measurements for VOC detection. Thus, the developed waveguide sensor has the potential to be used as a compact device module capable of monitoring multiple gaseous analytes for health, agricultural and environmental applications.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Volatile Organic Compounds
Type of study:
Diagnostic_studies
Language:
En
Journal:
Sci Rep
Year:
2022
Document type:
Article