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

Abstract

Cu-doped SnO2 films were deposited on glass slide substrate using an RF magnetron sputtering method. The effects of O2 partial pressures in the deposition process and post O2 plasma treatment were assessed for optical and sensing properties. O2 partial pressures from 2% to 10% were assessed. Post-plasma treatment used a 15 mL/min O2 flow, 450 °C annealing temperature and 30 min treatment time. Optical transmission spectra showed that the films deposited at higher O2 partial pressures had higher transparency and increased band gaps from 3.08 to 3.78 eV. After O2 plasma treatment, the films showed better than optical transmission. However, when the O2 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.