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

• Published in: Journal of materials research 2011-02, Vol.26 (3), p.430-436
• Main Authors: Parthangal, Prahalad, Cavicchi, Richard E., Meier, Douglas C., Herzing, Andrew, Zachariah, Michael R.
• Format: Article
• Language: English
• Subjects: Aluminum; Applied and Technical Physics; Atmospheric pressure; Biomaterials; Carbon; Charged particles; Chemical vapor deposition; CMOS; Electrodes; Electrons; Gases; Inorganic Chemistry; Materials Engineering; Materials research; Materials Science; Metal oxides; Nanoparticles; Nanotechnology; Nanowires; Nitrates; Semiconductors; Silicon wafers; Zinc oxides
• ISSN: 0884-2914; 2044-5326
• DOI: 10.1557/jmr.2010.27

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.