Controlling carrier density and its effect on I-V characteristics of the anatase-TiO2 thin films prepared by a sputter deposition method

TiO2 thin films were prepared by the inductively coupled Ar+-plasma sputtering method. The effects of O2 partial pressure on photoelectrochemical performance of the mainly anatase-TiO2 electrodes were studied. O2 partial pressure systematically affected the carrier density and the current-voltage characteristics of the electrodes. An electrode deposited at lowest O2 partial pressure (11 mPa) showed almost 3 orders of magnitude greater donor density and 4 times larger photocurrent compared to the one deposited at highest O2 partial pressure (52 mPa). The differences in current-voltage characteristics of the electrode samples are discussed on the basis of the space charge layer formation in the electrodes with different carrier densities.