Beschreibung:
<jats:p>We have fabricated single carbon nanowires (CNWs) suspended between carbon MEMS (CMEMS) structures with good Ohmic contacts employing photolithography, electrospinning and pyrolysis of SU8. By applying a current between the underlying CMEMS electrodes the CNW alone are Joule-heated, which initiate a chemical vapor deposition (CVD) process. We have successfully deposited a granular tungsten oxide (WO<jats:sub>3</jats:sub>) film by decomposing tungsten hexacarbonyl [W(CO)<jats:sub>6</jats:sub>] selectively onto these heated CNWs using this technique. WO<jats:sub>3</jats:sub> is a well known metal oxide semiconductor material extensively researched for its highly selective nitrogen oxide NO<jats:sub>x</jats:sub> sensing ability. It is a wide band-gap (~2.7 eV) n-type semiconductor material, which exhibits high sensitivity, quick response and an enhanced selectivity to detect NO<jats:sub>x</jats:sub> gases at low concentrations. The CNWs coated with WO<jats:sub>3</jats:sub> nanoparticles could become an invaluable addition to the nanosensor options as they might allow for NO<jats:sub>x</jats:sub> gas sensor fabrication with at an affordable cost. The W(CO)<jats:sub>6</jats:sub> to WO<jats:sub>3</jats:sub> conversion reaction takes place at 400-700<jats:sup>o</jats:sup>C,[30] which is likely the actual temperature of the CNW. In other words the CVD deposition temperature is a good indicator of the actual temperature and the temperature profile along the length of the CNW. In addition, this fabrication technique can be utilized for a wide variety of applications by depositing any desired material from a volatile precursor at elevated temperatures selectively on to CNWs.</jats:p>