Journal of Materials Research

Articles

Direct synthesis of tin oxide nanotubes on microhotplates using carbon nanotubes as templates

Prahalad Parthangala1, Richard E. Cavicchia2 c1, Douglas C. Meiera2, Andrew Herzinga2 and Michael R. Zachariaha3

a1 Departments of Mechanical Engineering and Chemistry, University of Maryland, College Park, Maryland 20742; and Chemical Science and Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899

a2 Chemical Science and Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899

a3 Departments of Mechanical Engineering and Chemistry, University of Maryland, College Park, Maryland 20742; and Chemical Science and Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899

Abstract

Tin oxide (SnO2) nanotubes have been synthesized using carbon nanotubes (CNTs) as removable templates. The entire synthesis takes place on the microscale on a micromachined hotplate, without the use of photolithography, taking advantage of the device’s built-in heater. Well-aligned multiwalled CNT forests were grown directly on microhotplates at 600 °C using a bimetallic iron/alumina composite catalyst and acetylene as precursor. Thin films of anhydrous SnO2 were then deposited onto the CNT forests through chemical vapor deposition of tin nitrate at 375 °C. The CNTs were then removed through a simple anneal process in air at temperatures above 450 °C, resulting in SnO2 nanotubes. Gas sensing measurements indicated a substantial improvement in sensitivity to trace concentrations of methanol from the SnO2 nanotubes in comparison with a SnO2 thin film. The synthesis technique is generic and may be used to create any metal oxide nanotube structure directly on microscale substrates.

(Received May 17 2010)

(Accepted October 04 2010)

(Online publication January 11 2011)

Correspondence:

c1 Address all correspondence to this author. e-mail: rcavicchi@nist.gov

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