Long-Term Stability Test for Femtosecond Laser-Irradiated SnO 2 -Nanowire Gas Sensor for C 7 H 8 Gas Sensing.

In this study, femtosecond (FS) laser irradiation with different laser energy densities of 138, 276, and 414 mJ/cm² is applied to SnO₂-nanowire (NW) gas sensors, and the effect of the FS laser irradiation on the gas sensor response toward toluene (C₇H₈) gas is investigated. The FS laser irradiation causes oxygen deficiency in the SnO₂ NWs and forms SnO and SnO_x. Moreover, an embossing surface with multiple nano-sized bumps is created on the SnO₂ NW surface because of the FS laser irradiation. The FS laser-irradiated SnO₂-NW gas sensor exhibits superior sensing performance compared with the pristine SnO₂-NW gas sensor. Moreover, the FS laser energy density significantly affects gas-sensing performance, and the highest sensor response is achieved by the gas sensor irradiated at 138 mJ/cm². The long-term stability test of the laser-irradiated SnO₂-NW gas sensor is performed by comparing fresh and 6-month-old gas sensors in different gas concentrations and relative humidity levels. Comparable gas-sensing behaviors are examined between the fresh and 6-month-old gas sensor, and this verifies the robustness of the laser-irradiated SnO₂-NW gas sensor. [ABSTRACT FROM AUTHOR]