Optical anisotropy of tungsten-doped ReS2 layered crystals

The optical anisotropy of tungsten-doped rhenium disulfide (ReS2:W) layered crystals have been studied by polarization and temperature dependent piezoreflectance (PzR) spectroscopy from 25 to 300 K. The direct band edge excitonic transitions E 1 e x feature at E∥b polarization and E 2 e x feature at E⊥b polarization of tungsten-doped ReS2 layered crystals were determined from a detailed line-shape fit of the PzR spectra. The PzR spectra reveal a slightly blue shifted of excitonic transition with the tungsten incorporation. The angular dependence of the excitonic feature amplitudes agrees with Malus' rule. The parameters that describe the temperature variation of the energies and broadening function of the excitonic transitions are determined and discussed.