A lead sulphide/lead titanate/silicon(PbS/PbTiO3/Si)heterostructure was manufactured by successive deposition ofPbTiO3and PbS thin film on a single crystalline,p-type, Si substrate. Chemical methods were used for deposition. A three electrode configuration was used to control the photoconductivity of PbS thin film by field effect, through the ferroelectricPbTiO3thin film. The spectral distribution of the photoconductive signal shows two maxima, situated at 1.1 and 2.45 &mgr;m. It was found that the photoconductive signal at 1 &mgr;m varies of about eight times when the voltage applied on the Si substrate is varied between−1and+1 V.At 2 &mgr;m the photoconductive signal is almost independent of the applied voltage on the Si substrate. The observed results are explained considering a ferroelectric field effect by which the photogenerated carriers in Si influence the photoconductive signal in the PbS thin film. ©1997 American Institute of Physics.