Nanoporous silicalite-only cantilevers as micromechanical sensors: Fabrication, resonance response and VOCs sensing performance

Nanoporous microcantilevers entirely constituted by silicalite type zeolite have been fabricated by integrating the seeded growth hydrothermal zeolite synthesis step in a conventional microfabrication scheme using Si technologies. The mechanical properties of the as prepared polycrystalline beams, ranging from 200 μm to 2000 μm in length and 20 to 120 μm in width have been fully characterized. In particular, Young modulus and quality factor of silicalite-only cantilevers before and after detemplation process have been determined by using mechanical resonance excitation and optical read-out. As a “proof of concept”, the nanoporous zeolitic cantilevers have been applied to ethanol detection at ppm level. The sensing performance of the as prepared silicalite-only cantilevers has been compared with the exhibited by conventional cantilevers consisting on microfabricated Si beams coated with individual silicalite crystals.