Optical and photoelectron-chemical properties of TiO_2 films by using hydrothermal method

摘要

In this paper, anatase TiO_2 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 TiO_2 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 TiO_2 film deposited for 0.5 M reaction concentration is 3.8 μA, which is higher than other samples.