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Articles you may be interested inPhotoreflectance and contactless electroreflectance measurements of semiconductor structures by using bright and dark configurations Rev. Sci. Instrum. 80, 096103 (2009); 10.1063/1.3213613 Interference effects in electromodulation spectroscopy applied to GaAs-based structures: A comparison of photoreflectance and contactless electroreflectance Determination of built-in field by applying fast Fourier transform to the photoreflectance of surface-intrinsic n +type doped GaAs Appl. Phys. Lett. 74, 475 (1999); 10.1063/1.123040 Micro-electroreflectance and photoreflectance characterization of the bias dependence of the quantum confined Stark effect in a fabricated 0.98 μm InGaAs/GaAs/InGaP laser Appl.Photoreflectance ͑PR͒ of surface-intrinsic-n ϩ (s-i-n ϩ ) type doped GaAs has been simulated by electroreflectance ͑ER͒. The simulated spectra of the s-i-n ϩ sample have exhibited many Franz-Keldysh oscillations, which enable the electric field ͑F͒ 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 Ϫ␦F/2 when the modulating field, ␦FӶF bi , where F bi is the built-in field of the sample and ␦F is the modulating field. In this work, we have investigated the relation between the measured F and ␦F not only for the region where ␦FӶF bi holds, but also for a whole range of ␦F. In order to determine the magnitude of ␦F, we have used ER to simulate PR, that is, the measurements of ER under a forward bias, which is set to be equal to ␦F/2.

The electroreflectance ͑ER͒ spectra of a surface-intrinsic n ϩ-type doped ͑100͒ GaAs have been measured at various polarization angles of the probe beam. Several Franz-Keldysh oscillations were observed above the band-gap energy, thus enabling heavy-and light-hole transitions to be separated by the application of the fast Fourier transform to the ER spectra. From this, the ratios of the amplitudes of the light-to heavy-hole transitions versus angle of polarization were obtained. At a large incident angle ͑80°͒, the strength of the field of the probe beam in the normal direction of the sample (F z) was varied from zero to a larger component. It was found that the ratios increased with increasing F z which is consistent with the theory that the light-hole transition becomes more enhanced with z-polarized light.