A novel miniature gas ionization sensor based on freestanding gold nanowires

Ramin Banan Sadeghian, Mojtaba Kahrizi

    Research output: Contribution to journalArticlepeer-review

    76 Citations (Scopus)


    Freestanding gold nanowires (AuNW) were incorporated to fabricate a miniaturized gas ionization sensor. The device exhibited improved sensitivity in sub-Torr pressure (P) regime compared to similar devices reported earlier, since the room temperature breakdown voltage (Vb) was further reduced in low gas pressures or concentrations (N). Also excellent selectivity was achieved for pressures up to 10 Torr, while Vb remained almost unaffected by pressure. In the Vb-P characteristic below 1 Torr, Vb was less when the AuNWs was configured as cathode, and it started to decline until a Paschen-like (Vb)min was observed at very low pressures (0.3 < P < 0.5 Torr). The reduction of breakdown voltage in this case, was attributed to the creation of an abnormally large amount of secondary electrons at the nanowire tips due to the increase in Townsend's secondary ionization factor (ω/α) at very high reduced fields (E/N). The pre-breakdown I-V characteristic of the device, obtained at extreme low pressures showed polarity dependency. The field enhancement factor (β) of the AuNW array was estimated by operating the device in the ohmic discharge region. The average aspect-ratio of the nanowires, which was extracted from the I-V characteristic, showed good agreement with SEM observations.

    Original languageEnglish
    Pages (from-to)248-255
    Number of pages8
    JournalSensors and Actuators, A: Physical
    Issue number2
    Publication statusPublished - 2007 Jul 4


    • Breakdown voltage
    • Field enhancement
    • Gas ionization sensor
    • Gold nanowires
    • Sub-Torr pressure

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Instrumentation
    • Condensed Matter Physics
    • Surfaces, Coatings and Films
    • Metals and Alloys
    • Electrical and Electronic Engineering


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