Detection of low concentration formaldehyde gas by photonic crystal sensor fabricated by nanoimprint process in polymer material
van Ee, R.J.
This paper describes experimental measurement results for photonic crystal sensor devices which have been functionalized for gas sensing applications. The sensor consists of a two dimensional photonic crystal etched into a slab waveguide having a refractive index of 1.7-1.9. Test devices were fabricated from SiON material on silicon/ silicon dioxide platform, and also in polymer materials on silicon platform. The inorganic photonic crystals were made using direct write electron-beam lithography and reactive ion etching. The polymeric devices were made by nano-imprint lithography using the SiON structure as the imprint master. The high refractive index polymer was composed of a TiO 2- UV resin nanocomposite having a nanoparticle fraction between 50 and 60 wt%. This resulted in a tunable refractive index between 1.7 and 1.85. Devices were functionalized for gas sensing applications by coating the surface with a chemical receptor. This responsive layer reacts with the target gas and changes its refractive index. This change causes the angle of out-coupling to change slightly. In this paper we report successful detection of formaldehyde in air at sub ppm levels, and discuss details of chemical functionalization of the PC sensor. cop. 2014 SPIE.
Mechanics, Materials and Structures
To reference this document use:
MIP - Materials for Integrated Products
TS - Technical Sciences
Electron beam lithography
Direct write electron-beam lithography
Gas sensing applications
High refractive index
Photonic crystal sensors
Two-dimensional photonic crystals
Optical Sensing and Detection III, 14-17 April 2014, Brussels, Belgium, 9141
Proceedings of SPIE - The International Society for Optical Engineering