Optical and photoelectron-chemical properties of TiO2 films by using hydrothermal method

In this paper, anatase TiO2 films have been prepared by hydrothermal method with different NaOH concentrations. The microstructures, optical and photoelectron-chemical properties of the as-deposited films were studied. SEM micrographs show the obtained films change from wave-like structure to one dimensional wire structure then to network structure. The average grain size of TiO2 thin films first increases and then decreases with increasing NaOH concentration. XPS measurement results exhibited the atomic ratio of Ti:O is estimated to be 1:2.21 for the sample deposited at 1 M. Band gaps obtained from UV–Vis absorption spectra shift from 3.29 to 2.23 eV with increasing reaction concentration. The photocurrent of TiO2 film deposited for 0.5 M reaction concentration is 3.8 µA, which is higher than other samples.