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J. Sama, P. Trompenaars, H. Mulders, S. Barth, A. Romano-Rodriquez:
"Platinum purification for higher conductive contacts for individual SnO₂ NWs gas sensor";
Poster: Annual Meeting of COST Action CM1301; Chemistry for Electron Induced NAnofabriction, Bratislava, Slavakei; 2015-05-06 - 2015-05-09; in: "2nd Annual Meeting of COST Action CM1301, CELINA - Book of Abstracts", (2015), 57.

Electron-beam induced Platinum deposition from C₅H₄CH₃Pt(CH₃)₃ precursor, usually employed in dual-beam FIB machines, has the main disadvantage of high carbon content, which gives rise to a low conductivity of the fabricated Pt nanostructures. A postprocessing of this nanostructure for diminishing its resistivity by about 5 orders of magnitude, as proposed by Mehendale et al. [1] and Villamor et al. [2], consists in applying high local oxygen flow close to the deposit while the electron beam is irradiating it, either heating the structure at 120ºC or keeping it at room temperature, respectively. On the other hand, individual SnO₂ nanowires have been implemented as a gas nanosensor for detecting the presence of toxic gases [3], contacting them by electron and ion beam induced Pt deposition. Due to the high resistance of Pt, part of the power supplied to the nanodevice for its operation is lost in the Pt accessing contacts. In this work, a combination of both methodologies has been attempted, consisting in SnO₂ NWs that have been contacted by purified electron beam induced Pt structures with the above mentioned approach. 4 probes electrical measurements show very low resistivity in the range of 102μΩ·cm, which is 2 orders of magnitude lower than other SnO₂ structures reported [4]. Ohmic behavior is obtained in 2-contacts I-V curves for all contacted NWs, which is related to the high conductivity of the NWs. The devices have been tested towards UV light exposure, showing response and decay times in agreement with other experimental values for metal oxide nanowires. The gas sensing has been monitored towards the presence of NO₂, CO and NH₃ in synthetic air, and no gas response has been observed. Possible explanation is that the surface of the metal oxide NWs might be affected by the purification process, causing the adsorption of oxygen molecules by chemisorption with high activation energy that were not desorbed with UV light.