Silicon surface‐barrier photodiodes have been fabricated and the steady‐state and time‐varying photoresponse have been measured. The photodiodes are operated in the reverse‐bias, or photoconductive mode at room temperature and do not require encapsulation. The average steady‐state photosensitivity is 0.31 &mgr;a/&mgr;w (&lgr;=5461 A) and 0.065 &mgr;a/&mgr;w (&lgr;=2537 A) with approximately 50 A of gold on the sensitive area. With no gold on the sensitive area, the photosensitivity is 0.37 &mgr;a/&mgr;w and 0.13 &mgr;a/&mgr;w, respectively. The photoresponse is uniform over the sensitive area (0.1 to 2.5 cm2) to within a few percent, depending on the wavelength. The high‐frequency cutoff is limited by the photodiode capacitance and load resistance. Cutoff frequencies greater than 100 kcps have been obtained. The operating characteristics of these devices are reported for six wavelengths lying in the range of approximately 0.2 to 0.6 &mgr;. The possibility of using photodiodes of this type in combination with a scintillator crystal for detecting charged particles is discussed.