Trilayer nanoimprint fabrication and simulation of the silicon nanowire sensor for gas detection

In this work, we demonstrate a novel SU8/SiO₂ /PMMA trilayer nanoimprint technique to fabricate the silicon nanowire (SiNW) sensor used for gas detection. The SiNW sensor fabricated in our experiment is based on the silicon on insulator (SOI) substrate which is doped by boron with a dopant concentration of 8 times 10¹⁷ cm^-3. Two nanowire sensors with different linewidths as well as a thin-film plane device were fabricated for comparison. The fabricated devices were then used for detecting 250 ppm NO₂ and 250 ppm NH₃. The results show a large enhanced sensitivity especially for the narrower device. Finally, a computer simulation work was done to qualitatively explain our experimental results.