ELECTROREFLECTANCE ANISOTROPY AT THE WSE2 LAYER SEMICONDUCTOR

The scanning microscope for semiconductor characterization (SMSC) was used to perform electrolyte electroreflectance (EER) measurements at the n-WSe2-iodide interface. The field dependence of the EER spectra was found to be in agreement with that predicted by Blossey's excitonic theory. A significant shift towards lower energies, without shape modification, was observed in EER spectra of defective (stepped) zones with respect to those corresponding to smooth regions. This effect was explained in terms of the optical anisotropy which characterizes the WSe2 layer semiconductor. The ground exciton energy (E1) of the smallest direct transition at the K point of the Brillouin zone was found to be higher along the c axis than perpendicular to it. A video image of the E1 surface distribution was obtained from SMSC measurements of the EER signal at constant wavelength.