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Title: Novel chemoresistive CH{sub 4} sensor with 10 ppm sensitivity based on multiwalled carbon nanotubes functionalized with SnO{sub 2} nanocrystals

Journal Article · · Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films
DOI:https://doi.org/10.1116/1.4936384· OSTI ID:22489764
;  [1]; ;  [2];  [3];  [4]
  1. Department of Electrical and Computer Engineering, University of Illinois, Chicago, Illinois 60607 (United States)
  2. Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439 (United States)
  3. Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
  4. U.S. Environmental Protection Agency, Las Vegas, Nevada 89199 (United States)

Chemoresistive sensors based on multiwalled carbon nanotubes (MWCNTs) functionalized with SnO{sub 2} nanocrystals (NCs) have great potential for detecting trace gases at low concentrations (single ppm levels) at room temperature, because the SnO{sub 2} nanocrystals act as active sites for the chemisorption of gas molecules, and carbon nanotubes (CNTs) act as an excellent current carrying platform, allowing the adsorption of gas on SnO{sub 2} to modulate the resistance of the CNTs. However, uniform conjugation of SnO{sub 2} NCs with MWCNTs is challenging. An effective atomic layer deposition based approach to functionalize the surface of MWCNTs with SnO{sub 2} NCs, resulting in a novel CH{sub 4} sensor with 10 ppm sensitivity, is presented in this paper. Scanning electron microscopy, transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy, and Raman spectroscopy were implemented to study the morphology, elemental composition, and the crystal quality of SnO{sub 2} functionalized MWCNTs. High resolution TEM images showed that the crystal quality of the functionalizing SnO{sub 2} NCs was of high quality with clear lattice fringes and the dimension almost three times smaller than shown thus far in literature. A lift-off based photolithography technique comprising bilayer photoresists was optimized to fabricate SnO{sub 2} functionalized MWCNTs-based chemoresistor sensor, which at room temperature can reliably sense below 10 ppm of CH{sub 4} in air. Such low level gas sensitivity, with significant reversible relative resistance change, is believed to be the direct result of the successful functionalization of the MWCNT surface by SnO{sub 2} NCs.

OSTI ID:
22489764
Journal Information:
Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films, Vol. 34, Issue 1; Other Information: (c) 2015 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0734-2101
Country of Publication:
United States
Language:
English

Cited By (1)