A system having an electronic device. The electronic device has an array of chemically sensitive sensors. The sensors detect volatile organic compounds and have field effect transistors. The transistors have non-oxidized, functionalized silicon nanowires. The nanowires have surface Si atoms. The device has a plurality of functional groups that form a direct Si—C bond with the silicon nanowires, wherein Si is a surface Si atom and C is a carbon atom of the functional group. The functional groups are selected from the group consisting of: alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heterocyclyl, heteroaryl, alkylaryl, alkylalkenyl, alkylalkynyl, alkylcycloalkyl, alkylheterocyclyl and alkylheteroaryl groups, and derivatives thereof, wherein said functional groups are other than methyl and 1-butyl. The plurality of functional groups are attached to 50-100% of the surface Si atoms.