An explanation is put forth for the observed nonlinearity in the red spectral region of the response of silicon photodiodes. Experiments are described to support the explanation; and the results, implications, and precautions indicated for the use of these diodes are given. Correlation of nonlinearity with spatial nonuniformity of response is demonstrated.
A. R. Schaefer, E. F. Zalewski, and Jon Geist, "Silicon detector nonlinearity and related effects," Appl. Opt. 22, 1232-1236 (1983)