Formation and gas-sensing properties of a porous-alumina-assisted 3-D niobium-oxide nanofilm

Formation and gas-sensing properties of a porous-alumina-assisted 3-D niobium-oxide nanofilm

WoS Article

For advanced gas-sensing applications, we have synthesized a 3-dimensional (3-D) metal/oxide/metal nanofilm that merges the benefits of advanced composite inorganic materials with the flexibility of non-lithographic electrochemical technologies based on so-called porous-anodic-alumina-assisted anodizing of a refractory metal and the original point electrodeposition of noble metals. The film is composed of an NbO2 layer, 200 nm thick, with upright-standing Nb2O5 nanocolumns (diameter ∼50 nm, length 900 nm, density 8 × 109 cm−2), which work as semiconducting nano-channels, assembled between two parallel metal electrodes, whose resistivity measured along the columns is greatly impacted by the surface and interface reactions. A laboratory microdevice employing the 3-D niobium-oxide nanofilm, mounted on a standard TO-8 package, revealed asymmetric electron transfer properties due to a Schottky barrier formed at the Au/Nb2O5 interface, resistive switching mechanism in the film, and superior characteristics for hydrogen and, especially, ethanol detection with best response times to 1000 ppm H2 and 500 ppm H2C6O being 3 and 1 min, respectively. A computer-aided simulation of gas diffusion in the 3-D nanofilm predicts a possibility to substantially improve sensor performance through the formation of a perforated top electrode and by introducing certain innovations in the electrode design.

For advanced gas-sensing applications, we have synthesized a 3-dimensional (3-D) metal/oxide/metal nanofilm that merges the benefits of advanced composite inorganic materials with the flexibility of non-lithographic electrochemical technologies based on so-called porous-anodic-alumina-assisted anodizing of a refractory metal and the original point electrodeposition of noble metals. The film is composed of an NbO2 layer, 200 nm thick, with upright-standing Nb2O5 nanocolumns (diameter ∼50 nm, length 900 nm, density 8 × 109 cm−2), which work as semiconducting nano-channels, assembled between two parallel metal electrodes, whose resistivity measured along the columns is greatly impacted by the surface and interface reactions. A laboratory microdevice employing the 3-D niobium-oxide nanofilm, mounted on a standard TO-8 package, revealed asymmetric electron transfer properties due to a Schottky barrier formed at the Au/Nb2O5 interface, resistive switching mechanism in the film, and superior characteristics for hydrogen and, especially, ethanol detection with best response times to 1000 ppm H2 and 500 ppm H2C6O being 3 and 1 min, respectively. A computer-aided simulation of gas diffusion in the 3-D nanofilm predicts a possibility to substantially improve sensor performance through the formation of a perforated top electrode and by introducing certain innovations in the electrode design.

Niobium oxide; Anodizing; Anodic alumina; 3-D nanostructure; Hydrogen; Ethanol; Gas sensor

Niobium oxide; Anodizing; Anodic alumina; 3-D nanostructure; Hydrogen; Ethanol; Gas sensor

MOZALEV, A.; BENDOVÁ, M.; VAZQUEZ, R.; PYTLÍČEK, Z.; LLOBET, E.; HUBÁLEK, J.

2017

28.06.2016

0925-4005

SENSORS AND ACTUATORS B-CHEMICAL

229

Swiss Confederation

587

598

12

http://www.sciencedirect.com/science/article/pii/S0925400516301733