TEMPERATURE DEPENDENCE OF HOMOGENEOUS ANATASE-PHASED TiO2 FILMS CHARACTERIZATION AND GAS-SENSING BEHAVIORS

Anatase-phased TiO2 films were prepared at different temperatures (350, 400, 450 and 500 degrees C) using automated nebulizer spray pyrolysis (ANSP) method. The structural study (XRD) revealed the amorphous nature at 350 degrees C and remaining samples (400, 450 and 500 degrees C) show the tetragonal structure with 2 theta degrees=25.78, 38.43, 48.49 and 55.54 corresponding to (101), (004), (200) and (105) reflected planes and it is well fitted with standard data. The compositional XPS analysis confirmed the core level primary element of Ti 2p, O 1s and valance band (VB) of Ti 3p, Ti 3s, O 2s peaks in the prepared samples. The 3D optical profilometer has shown that the thickness of the prepared films was decreased by increase in temperature. The AFM study exhibited average roughnesses (Ra) of the prepared films such as 0.058, 0.147, 0.176 and 0.194 nm, respectively. The surface morphological study of FESEM has shown the cracked uneven distributed nature (350 degrees C) turn into evenly distributed closed packed agglomerated particles by the influence of temperature. The oscillating nature of transmittance (%) with redshift of the sharp absorption edge was observed in UV-Vis-NIR spectrophotometer and found the bandgap value about 3.58 eV to 3.33 eV through Tauc's relation. The gas-sensing behavior has shown better response to C2H6O reducing gas at 300 degrees C operating temperature with 150 ppm gas concentration.