Optical properties of rhenium diselenide single crystals doped with transition metals

Abstract

In this paper, we focus on optical properties of rhenium diselenide (ReSe2) single crys- tals doped with Au, W, and Nb. The doping effect of the material was characterized by polarization-dependent piezoreflectance (PzR) and photoreflectance (PR) measurements in the temperature range of 15–300 K. The low temperature PzR and PR spectra reveal the observation of ex E1 feature at E||b polarization as well as two features ex E2 and exE3 at E⊥b polarization. In comparison with the undoped ReSe2, the excitonic transition energies remain practically unchanged, while the broadening parameter of the excitonic transition features slightly increases due to impurity scattering. The angular dependence of the excitonic features amplitudes agree well with the Malus law.