A three terminal (transistor-like) photodetector fabricated on a silicon-on-insulator substrate with a high responsivity over a wide spectral range from ultraviolet to the near infrared is described. Even for low gate and drain voltages of -0.15 V and +1 V, respectively, its responsivity is 0.5 A/W at 315 nm, 0.63 A/W at 455 nm, and 0.26 A/W at 880 nm. Moreover, the device exhibits a negative differential resistance (due to Pt nano particles which are embedded within the gate dielectric) with large peak-to-valley current ratios of 60 in the dark and up to 140 under illumination. These values are several times larger than those obtained in alternative two or three terminal systems which are based on heterostructures or structures with extremely high doping regions that cause band-banding or resonant tunneling. © 2016 Author(s).