Effect of modulating field on photoreflectance simulated by electroreflectance

Abstract

Photoreflectance (PR) of surface-intrinsic- n(+) (s-i-n(+)) type doped GaAs has been simulated by electroreflectance (ER). The simulated spectra of the s-i-n(+) sample have exhibited many Franz-Keldysh oscillations, which enable the electric field (F) to be determined. It is known that F's determined from PR are subjected to photovoltaic effect and the measured F is close to F-bi -delta F/2 when the modulating field, delta F much less than F-bi, where F-bi is the built- in field of the sample and delta F is the modulating field. In this work, we have investigated the relation between the measured F and delta F not only for the region where delta F much less than F bi holds, but also for a whole range of delta F. In order to determine the magnitude of dF, we have used ER to simulate PR, that is, the measurements of ER under a forward bias, which is set to be equal to delta F/2. (C) 1999 American Institute of Physics. [S0021-8979(99)01906-4].