Fluorine-implanted indium-gallium-zinc oxide (IGZO) chemiresistor sensor for high-response NO2 detection

Gas sensors fabricated using In-Ga-Zn oxide (IGZO) thin films doped with Fluorine (F) were used to detect nitrogen dioxide (NO2) gas. IGZO films with a thickness of 250 nm were deposited onto SiO2/Si substrates via radio-frequency magnetron sputtering, followed by F-doping by an ion-implantation procedure with implant energy of 45 keV and a dose of 3 x 10(15) ions/cm(2). The NO2 gas detection performance of the fabricated thin-film sensors was tested at various temperatures and NO2 concentrations. The F-doped IGZO (F-IGZO) sensor showed high NO2 gas sensitivity: the ratio between the responses to NO2 and air (R-gas/R-air) was 590 at 250 degrees C and 100 ppm NO2 gas concentration. F-IGZO sensor showed superior selectivity toward NO2 over other gases. The stability of the sensor was also investigated; the sensor was observed to exhibit stable performance for 2 weeks.