Photoelectrochemical properties of hematite thin films grown via a two-step electrochemical deposition method

In this study, Fe2O3 thin films were deposited via one-step and two-step electrochemical deposition methods. The one-step method used a constant growth potential, and the two-step method used two continuous growth potentials during the deposition. The morphological, electrical, and structural properties of the thin films and the relationships of each property with the photoelectrochemical properties of the thin films from the two methods were analyzed and compared. We determined that the samples grown by the two-step method have better photoelectrochemical properties than those grown by the one-step method. In this study, we attempted to determine the optimum growth potentials for the one-step and two-step methods and the growth durations of the first and second stages in the two-step method in terms of the photoelectrochemical properties. The sample formed at −0.05 V for 30 s in the first step and −0.25 V for 2 min 30 s in the second step in the two-step method has the highest photocurrent density value of 0.28 mA/cm2 (at 0.5 V vs. SCE), which is higher than that of the samples grown by the one-step method.