Nanoscale chemiresistor arrays with patterned nanoparticle interface layers for micro gas chromatography

Chemiresistor (CR) arrays with nanoscale electrode features and crosslinked thiolate-monolayer-protected gold nanoparticle (MPN) sensing layers were fabricated and characterized. These arrays, intended for ultimate use as detectors in a micro-scale gas chromatograph, employ interdigital electrodes (10 mum finger length with 100 nm width and spacing) patterned by electron-beam lithography. Films of different MPNs were sequentially deposited on the electrodes and crosslinked by electron-beam exposure. Responses to vapors were compared with those from a reference array with uncrosslinked films. Differences in sensitivities and response patterns between crosslinked and uncrosslinked arrays with the same MPN films are rationalized in terms of structural changes in the MPN ligands and related changes in vapor sorption by the films.