Improved Transparent Gas Sensor Properties of Cu-Doped SnO₂ Films using O₂ Plasma Treatment

Abstract

Abstract Cu-doped SnO 2 films were deposited on glass slide substrate using an RF magnetron sputtering method. The effects of O 2 partial pressures in the deposition process and post O 2 plasma treatment were assessed for optical and sensing properties. O 2 partial pressures from 2% to 10% were assessed. Post-plasma treatment used a 15 mL/min O 2 flow, 450 °C annealing temperature and 30 min treatment time. Optical transmission spectra showed that the films deposited at higher O 2 partial pressures had higher transparency and increased band gaps from 3.08 to 3.78 eV. After O 2 plasma treatment, the films showed better than optical transmission. However, when the O 2 partial pressure increased to 10%, the optical transmission declined slightly because the film had higher surface roughness, smaller crystals and fewer oxygens in the parent rutile tetragonal cells, enhanced the sensor response at room temperature.