In this report, we have synthesized Bornite (Cu5FeS4) material by hydrothermal synthesis technique. The interface characteristics of Al/Cu5FeS4/FTO Schottky barrier diode (SBD) are investigated by using ac impedance spectroscopy (IS) analysis (under dark condition) and dc current-voltage (I-V) measurements (under dark and light both condition). IS is a powerful tool to identify the interface regions of SBDs. Ac impedance spectra of Al/Cu5FeS4 SBD are recorded in the frequency range 40 Hz-20 MHz during dc bias scanning from -0.6 V to 0.6 V under dark condition. The diode parameter including ideality factor and barrier height is calculated from the conventional I V measurement based on thermionic emission (TE) theory. Space charge limited current (SCLC) theory has been employed to further exemplify the improved performance of Cu5FeS4 based SBD, which points out that the carrier mobility is enhanced similar to 2-fold after irradiation of light.