This work aims to explore the effects of Sr+2 concentrations on the growth of SrTiO3 thin films synthesized by the hydrothermal-galvanic couple method. The syntheses were conducted on the TiN/Si substrates in 2 M NaOH solutions consisting of various Sr+2 concentrations at 80 degrees C. Cubic SrTiO3 films were formed at Sr+2 concentrations above 0.0004 M. Epitaxial-like growth of the SrTiO3 films was found over the TiN underlayer at such various Sr+2 concentrations. The relative diffraction peak intensity, the grain size, and the thickness of the obtained SrTiO3 films first increased rapidly, then reached the maximum, and decreased gradually afterwards with increasing the Sr+2 concentrations. The grain size and the thickness of the films would reach the maximum at 0.001 M [Sr+2]. Nanograins of the films were present at high Sr+2 concentrations. The growth kinetics of the films was determined by a modified Avrami-Erofe'ev equation. Nucleation governs the formation of SrTiO3 at high Sr+2 concentrations, leading to the nanograins. Grain growth predominates at low Sr+2 concentrations, yielding the large grains. Moreover, both the dielectric constant and the dielectric loss of the obtained SrTiO3 films increased with decreasing the Sr+2 concentrations. (C) 2014 Elsevier B.V. All rights reserved.