Bulk measurement of the franz-keldysh effect in Si

Results of bulk measurements of the Franz-Keldysh effect in Si at -35°C and -191°C are presented in this paper. Use is made of a special-purpose computer in order to obtain very long integration time without drift, which in turn made the performance of a high-resolution measurement possible. The measured change in absorption caused by the applied electric field as a function of photon energy displays considerably more structure than previously reported. The position of the different peaks in photon energy is found to be independent of the applied electric field. Consequently, the peaks are interpreted as different phonon processes. The absolute value of the change in absorption was found to be proportional to the applied electric field to the 1.72 power which is closer to the theoretically expected value of 1.33 than is the value of 2 previously reported.