Piezoreflectance Study of Band-Edge Excitons of ReS2:Au

The optical properties of Au-doped rhenium disulphide (ReS2:Au) have been investigated by temperature- and polarization-dependent plezoreflectance (PzR) measurements. In comparison with the undoped ReS2:Au shows not only the main excitonic transitions of E-1(ex), E-2(ex), E-3(ex) and E-4(ex) near the direct band edge but also two extra transitions E-A(ex) and E-B(ex) owing to the doping effects. From temperature- dependent PzR spectra in the temperature range from 40 to 300 K, the least-squares fits are used to extract the parameters that describe the temperature variations of the band-edge excitonic transitions. The excitonic transitions show a strong polarization dependence in the near infrared region. The polarization-dependent PzR measurement in the range between 0 and 180 degrees was used to characterize the unique polarization property of ReS2:Au, and identify the origin of the excitonic transitions. However, the variation in the amplitude of PzR excitonic transitions with different polarization characteristics follows the Malus rule. (C) The Japan Society of Applied Physics