title: Fabrication of a sub-10 nm silicon nanowire based ethanol sensor using block copolymer lithography.
abstract: This paper details the fabrication of ultrathin silicon nanowires (SiNWs) on a silicon-on-insulator (SOI) substrate as an electrode for the electro-oxidation and sensing of ethanol. The nanowire surfaces were prepared by a block copolymer (BCP) nanolithographic technique using low molecular weight symmetric poly(styrene)-block-poly(methyl methacrylate) (PS-b-PMMA) to create a nanopattern which was transferred to the substrate using plasma etching. The BCP orientation was controlled using a hydroxyl-terminated random polymer brush of poly(styrene)-random-poly(methyl methacrylate) (HO-PS-r-PMMA). TEM cross-sections of the resultant SiNWs indicate an anisotropic etch process with nanowires of sub-10 nm feature size. The SiNWs obtained by etching show high crystallinity and there is no evidence of defect inclusion or amorphous region production as a result of the pattern transfer process. The high density of SiNWs at the substrate surface allowed the fabrication of a sensor for cyclic voltammetric detection of ethanol. The sensor shows better sensitivity to ethanol and a faster response time compared to widely used polymer nanocomposite based sensors.
authors: Materials Chemistry Section, Department of Chemistry, University College Cork, College Road, Cork, Ireland.
authors: Sozaraj
authors: S
authors: Rasappa
authors: Dipu
authors: D
authors: Borah
authors: Colm C
authors: CC
authors: Faulkner
authors: Tarek
authors: T
authors: Lutz
authors: Matthew T
authors: MT
authors: Shaw
authors: Justin D
authors: JD
authors: Holmes
authors: Michael A
authors: MA
authors: Morris