Gallium nitride (GaN) films were synthesized on n-type-Si (111) substrates using a low-cost and low-temperature technique of electrochemical deposition. The electrochemical behavior of Ga3+, NH4+, and NO3- ions in the aqueous solutions used as sources of GaN were confirmed by cyclic voltammetry. The scanning electron microscopy images showed that the films deposited at a current density of 3.5 mA cm(-2) or greater have plate-like surface morphologies on the Si substrate. The energy-dispersive X-ray spectroscopy results showed that oxygen, gallium, and nitrogen coexist in these plate-like films. In the X-ray diffraction patterns, the sample synthesized at a current density of 3.5 mA cm(-2) for 24 h exhibited peaks of gallium oxide and hexagonal-GaN phase. Photoluminescence analysis revealed a peak at 3.2 eV, which corresponds to the band gap energy of GaN, as well as a broad peak at around 2.5 eV at room temperature. Graphic abstract