UV-assisted alcohol sensing using SnO2 functionalized GaN nanowire devices

摘要: Abstract A chemiresistor type sensor for selective alcohol sensing has been realized from gallium nitride (GaN) nanowires (NWs) functionalized with sputter-deposited tin dioxide (SnO2) nanoparticles. Two-terminal devices were fabricated using standard microfabrication techniques the individual NWs air-bridged between two metal contact pads. Through a combination of X-ray diffraction (XRD), electron-backscatter-diffraction (EBSD), and TEM/STEM techniques, we confirmed presence rutile SnO2 nanocrystals on GaN surface. change in device current is observed when exposed to vapors (methanol, ethanol, propanol, butanol) at room temperature under 215–400 nm UV illumination 3.75 mW/m2 intensity 365 nm wavelength. The reproducibly responded wide range vapor concentrations, 5000 μmol/mol (ppm) down 1 μmol/mol air. Notably, show low sensitivity acetone hexane, which allows them selectively detect primary mixed these common volatile organic compounds (VOCs). response was not without excitation. From experimental results found relationship towards length carbon chain molecule: chemiresistive decreases increasing methanol n-butanol. In addition, that isomeric branching i-propanol i-butanol caused reduced as compared n-propanol n-butanol, respectively. We have qualitatively explained operation by employing mechanism, includes oxidation analyte molecules surface, leading enhanced photoconductivity nanowire.