Photoreflectance spectroscopy of CdTe(001) around E1 and E1+Δ1:: linear electro-optic spectrum

We report on the measurement of the linear electro-optic (LEO) reflectance spectrum of CdTe (001) in an energy range around the E-1 and E-1 + Delta(1) interband transitions. This spectrum shows a sharp peak localized in energy around E-1 and a second shorter peak around E-1 + Delta(1). We show that the theoretical model developed in an earlier article for the LEO line shape of GaAs (001) gives an accurate description of the experimental LEO CdTe spectrum as well. This model includes two contributions to the LEO line shape, a first one proportional to the normalized energy derivative of the reflectance spectrum and a second one associated to the sample reflectance. The large spin-orbit splitting energy of CdTe, (Delta(1) approximate to 0.6 eV) allows for a neat separation of the contributions to the LEO spectrum of the E-1 and E-1 + Delta(1) critical points, providing a critical test for the LEO line shape model. From the fitting we obtain d'/d = 1.5 for the conduction band to valence band deformation potential ratio and E-2 = 9.1 eV for the interband deformation potential in the Brooks notation. (C) 1999 American Institute of Physics. [S0021-8979(99)02416-0].