A photodetector based on Mg/ZnSnP2/Sn structure was fabricated on p-type silicon (100) to operate in the wavelength range of 450-850 nm. The observed current-voltage characteristics showed roll-over like features which was successfully modeled considering two Schottky junction diodes connected back to back. The device showed strong photo-response in both the forward and reverse bias configuration and the current-voltage curve shifted to the fourth quadrant under illumination. The barrier height and the ideality factor of the two Schottky diodes were evaluated using numerical simulation. The maximum values of responsivity, photosensitivity and detectivity were found to be 22.76 mA W-1, 57.00 cm(2)W(-1) and 6.34 x 10(10) cm Hz(1/2) W-1 in the forward bias and 3.48 mA(-1), 48.22 cm(2) W-1 and 2.25 x 10(10) cm Hz(1/2) W-1 in the reverse bias, respectively at illumination of wavelength 850 nm. The photodetector showed a fast response time of 47 is and multiple recovery times of 725 mu s, 1.2 ms and 1.3 ms respectively. The existence of traps within the ZnSnP2 thin films was responsible for extending the time of recovery in comparison to time of response.