Highly sensitive detection of sarin simulant by a functional SiNW array

Highly sensitive and specific detection of dimethyl methylphosphonate (DMMP), a typical sarin simulant, was demonstrated by silicon nanowire (SiNW) array sensor. The SiNW array devices were fabricated by conventional microfabrication methods and self-assembled with the sensitive material bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane to obtain unique sensitivity to the DMMP vapor. Effect of surface functionalization parameters on DMMP sensing was optimized to increase the adsorption site number density for specific binding of DMMP. The optimized SiNW array sensor showed a high sensitivity to DMMP vapor in a detection limit of 0.2 ppm. Role of the SiNWs array is proposed to possess an extremely large surface area for a hydrogen bond-mediated recognition of the P = O group in DMMP. These initial promising results offer an alternative tool for fabrication and modification of highly sensitive, reliable and low-cost SiNW sensors to detect DMMP. Graphical abstract