(CANCELED) Highly selective sensing of DMMP and NH3 using CNTFET array based gas sensors obtained using Spray-gun technique and fabricated with different metal electrodes to achieve gas electronic fingerprinting
P. Bondavalli, P. Legagneux, D. Pribat, L. Gorintin
Thales Research and Technology, FR
Keywords: CNTFET, SWCNT mat, Selective sensing, gas sensors
Abstract:This paper deals with the prove of concept of an highly selective gas sensor based on CNTFETs which exploits the extremely sensitive change of the Schottky barrier heights between SWCNTs and metal electrodes. Specifically, the gas electronic fingerprinting concept is based on the fact that the change of the metal electrode work function strictly depends on the metal/gas interaction. Therefore the CNTFET transfer characteristics (IDS (VG)) change specifically as a function of this interaction. After having demonstrated that using Au, Pd, Pt metals we achieve a change of the IDS (VG) which is different for each transistor after exposure to 2ppm of DMMP (nerve agent-simulant) : current reduction of 90% for Pd, 80% for Au and 20% for Pt. To father implement our demonstration, we have fabricated different CNTFETs using more metal contacts (Au, Pd, Mo, Pt, Ti, Ni) and exposed our array to a subppm concentration of 0.5ppm of DMMP and NH3 (gas with the same “withdrawing” character) identifying two different electronic fingerprinting. Tests using Acetic anhydride, an heroin precursor, will also be shown. Our work demonstrates that this new approach can be applied for highly selective, versatile sensing of a large number of gases using ultra-compact, room temperature and very low power devices.