Structural, morphological, optical and gas sensing properties of pure and Ce doped SnO_2 thin films prepared by jet nebulizer spray pyrolysis (JNSP) technique

摘要

Pure and cerium (Ce) doped tin oxide (SnO_2) thin films are prepared on glass substrates by jet nebulizer spray pyrolysis technique at 450 ℃. The synthesized films are characterized by X-ray diffraction (XRD), scanning electron microscopy, energy dispersive analysis X-ray, ultra violet visible spectrometer (UV-Vis) and stylus profilometer. Crystalline structure, crystallite size, lattice parameters, texture coefficient and stacking fault of the SnO_2 thin films have been determined using X-ray diffractometer. The XRD results indicate that the films are grown with (110) plane preferred orientation. The surface morphology, elemental analysis and film thickness of the SnO_2 films are analyzed and discussed. Optical band gap energy are calculated with transmittance data obtained from UV-Visible spectra. Optical characterization reveals that the band gap energy is found decreased from 3.49 to 2.68 eV. Pure and Ce doped SnO_2 thin film gas sensors are fabricated and their gas sensing properties are tested for various gases maintained at different temperature between 150 and 250 ℃. The 10 wt% Ce doped SnO_2 sensor shows good selectivity towards ethanol (at operating temperature 250 ℃). The influence of Ce concentration and operating temperature on the sensor performance is discussed. The better sensing ability for ethanol is observed compared with methanol, acetone, ammonia, and 2-methoxy ethanol gases.