Nanostructured α-Fe2O3 thin films were grown by plasma-enhanced chemical vapor deposition (PE-CVD) using iron pentacarbonyl (Fe(CO)5) as precursor. Influence of the plasma parameters on photoelectrochemical (PEC) properties of the resulting hematite thin films toward solar oxidation of water was investigated under one sun illumination in a basic (1 M NaOH) electrolyte. PEC data analyzed in conjunction with the data obtained by scanning electron microscopy, X-ray diffraction and Mott–Schottky analysis showed 100 W plasma power to be an optimal RF-power value for achieving a high photocurrent density of ∼1098 μA/cm2 at 0.9 V/SCE external applied potential. The donor density, flat band potential, grain size and porosity of the films were observed to be highly affected by RF-power, which in turn resulted in enhanced photoresponse.