SnO2 nanowires for optical and optoelectronic gas sensing

Quasi-1D nanostructures of metal-oxide semiconductors have been extensively investigated for their novel physical properties and have found application in electronics, photonics and gas sensing. Among them, SnO₂ is a typical n-type semiconductor with a wide band gap of 3.6 eV, showing a broad visible photoluminescence (PL) emission. Moreover, SnO₂ nanowires irradiated with UV-visible radiation (near their band gap) show a great increase of conductance and photocurrent (PC) is generated, if a constant potential is applied. PL emission and PC generation are strongly dependent on surface states and can thus be tuned depending on the surrounding atmosphere. In this work, we compared the optical and optoelectronic properties of SnO₂ nanowires synthesized via evaporation-condensation (EC) process. Photoluminescence emission and photocurrent flowing through biased SnO₂ nanowires were studied in various gas atmospheres, targeting NO₂ and ethanol sensing applications.