Linear electro-optic reflectance modulated spectra of GaAs (001) around E-1 and E-1+Delta(1)

We report on the determination of the linear electro-optic (LEO) reflectanc e modulated spectra of GaAs (101). LEO spectra were obtained from photorefl ectance (PR) measurements. Experiments were carried out in an energy range around the E-1 and E-1 + Delta (1) interband transitions. Two samples were employed, an undoped homepitaxial GaAs and a GaAs bulk crystal doped with T e donors in the low 10(17)/cm(3) range. We show that, although LEO spectra amplitudes for the two samples differ for one order of magnitude, their lin e shape is essentially the same. We further report on reflectance-differenc e (RD) measurements aimed to obtain LEO spectra. We employed the same GaAs samples for, both, PR and RD measurements in order to contrast the informat ion provided by these two techniques. (C) 2000 Elsevier Science S.A. All ri ghts reserved.