We report optically sensitive multi-functional metal-insulator-semiconductor devices based on Pt nanoparticles, which were fabricated in-situ with the dielectric stack using atomic layer deposition on a silicon-on-insulator substrate. The devices exhibit non-volatile memory behavior, with a memory window that can be enhanced by optical illumination. Voltage stressed devices serve as highly sensitive broadband photodetectors, as well as optically tunable varactors. © 2015 IEEE.