Polarization sensitive behaviour of the band-edge transitions in ReS 2 and ReSe2 layered semiconductors

Abstract

The polarization sensitive behaviour of the band-edge transitions in ReS2 and ReSe2 layered compounds was studied using polarized-transmission and polarized-thermoreflectance (PTR) measurements with polarization angles from θ = 0° (E ∥ b-axis) to θ = 90° (E ⊥ b-axis) at 300 K. The polarization dependence of the polarized energy gaps of ReS2 and ReSe2 shows a sinusoidallike variation with respect to the angular change of the linearly polarized light. The angular dependences of the polarized energy gaps of ReS2 and ReSe 2 were evaluated. The polarization sensitive behaviour of the band-edge excitons in rhenium disulfide and diselenide was characterized using angular dependent PTR measurements from θ = 0° to 90°. The polarized transition intensities of the band-edge excitons (E1ex and E2ex) ReX2 (X = S, Se) demonstrate a sinusoidal variation with respect to the angular change of the linearly polarized light. The angular dependence of the polarized transition probabilities of E1ex and E2ex is analysed. The polarization sensitive behaviours of ReX2 (X = S, Se) layers are discussed.