Gas Sensing of Chemical Vapor Deposition-Formed Zinc-Doped Indium Oxide Nanowires

Although indium oxide has been extensively utilized for gas detection of pollutants, it is still possible to further improve the gas sensitivity and selectivity. Here, we fabricated zinc-doped indium oxide nanowires of excellent morphologies and high crystallinity via chemical vapor deposition. Electrical measurements by a single-nanowire microdevice reveal that doping of zinc contributed to the increasing electrical resistivity; as an acceptor, the lower valence of the dopant caused the decreasing electrical conductivity. X-ray photoelectron spectroscopy analysis demonstrates the increasing oxygen vacancies from appropriate doping, changing oxygen adsorption on the nanowires, which led to enhanced gas sensing properties. Reducing gases, including carbon monoxide, acetone, and ethanol, were utilized to judge the sensing ability. It turns out that the response of the doped nanowires was higher than that of undoped ones at 5 ppm and low temperatures; the gas sensing response of zinc-doped In 2 O 3 nanowires was 13 times higher than that of undoped In 2 O 3 nanowires at 300°C. Consequently, higher zinc doping concentration in In 2 O 3 nanowires enhanced gas sensing performance with increasing oxygen vacancies from doping and improving gas molecule adsorption. Zinc-doped In 2 O 3 nanowires can be attractive choices for environmental detection and life science.