Lupan, O., Postica, V., Marx, J., Mecklenburg, M., Mishra, Y. K., Schulte, K., Fiedler, B. and Adelung, Rainer (2017) Individual hollow and mesoporous aero-graphitic microtube based devices for gas sensing applications. Applied Physics Letters, 110 (26). DOI 10.1063/1.4989841.

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Abstract

In this work, individual hollow and mesoporous graphitic microtubes were integrated into electronic devices using a FIB/SEM system and were investigated as gas and vapor sensors by applying different bias voltages (in the range of 10 mV–1 V). By increasing the bias voltage, a slight current enhancement is observed, which is mainly attributed to the self-heating effect. A different behavior of ammonia NH3 vapor sensing by increasing the applied bias voltage for hollow and mesoporous microtubes with diameters down to 300 nm is reported. In the case of the hollow microtube, an increase in the response was observed, while a reverse effect has been noticed for the mesoporous microtube. It might be explained on the basis of the higher specific surface area (SSA) of the mesoporous microtube compared to the hollow one. Thus, at room temperature when the surface chemical reaction rate (k) prevails on the gas diffusion rate (DK) the structures with a larger SSA possess a higher response. By increasing the bias voltage, i.e., the overall temperature of the structure, DK becomes a limiting step in the gas response. Therefore, at higher bias voltages the larger pores will facilitate an enhanced gas diffusion, i.e., a higher gas response. The present study demonstrates the importance of the material porosity towards gas sensing applications.

Document Type:	Article
Research affiliation:	Kiel University > Kiel Marine Science OceanRep > The Future Ocean - Cluster of Excellence
Refereed:	Yes
Open Access Journal?:	No
Publisher:	American Institute of Physics
Projects:	Future Ocean
Date Deposited:	12 Dec 2017 13:58
Last Modified:	06 May 2019 11:12
URI:	https://oceanrep.geomar.de/id/eprint/40558

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