Photoreflectance spectroscopy of CdTe(001) around E-1 and E-1+Delta(1): 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 energ y 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 shap e of GaAs (001) gives an accurate description of the experimental LEO CdTe spectrum as well. This model includes two contributions to the LEO line sha pe, a first one proportional to the normalized energy derivative of the ref lectance spectrum and a second one associated to the sample reflectance. Th e large spin-orbit splitting energy of CdTe, (Delta(1) approximate to 0.6 e V) 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 con duction band to valence band deformation potential ratio and E-2 = 9.1 eV f or the interband deformation potential in the Brooks notation. (C) 1999 Ame rican Institute of Physics. [S0021-8979(99)02416-0].