RESUMO
This work focuses on the compositional dependences in parameters that govern the optical properties of (GeTe)x(Sb2Te3)1-x amorphous alloys in the wide spectral range from above the phonons and to the inter-band electronic transitions. We studied the absorption edge fluctuations that are linked to the variations of the bandgap Eg, the width of Urbach-Martienssen tails EU, the Tauc parameter B1/2, and average halfwidth
RESUMO
Here we report on the analysis of the effect of the doping of CdP2 single crystals by ZnP2 nanoclusters on the dispersion of the surface polaritons (SP). The ATR spectroscopic technique has been applied to excite the SP in the CdXZn(1-X)P2 system. Analysis of the obtained spectra has shown that the doping of CdP2 single crystals by ZnP2 nanoclusters result in the position and the width of the dispersion branches of the SP. This effect is more pronounced in the low frequency dispersion branches. These SP branches are originated from phonons which correspond to the motion of the cation sublattice.
RESUMO
Zinc germanium diphosphide (ZnGeP2) is an attractive and promising functional material for different devices of the nano- and optoelectronics. In this paper, dispersion of phonon surface polaritons (PSPs) in ZnGeP2 has been studied in the 200-500-cm(-1) spectral range at 4 and 300 K. Dispersion of "real" and "virtual" PSPs were calculated for C-axis being normal and parallel to the surface. Anisotropy in ZnGeP2 leads to the different numbers of PSP dispersion branches for different orientations of the sample. The temperature-dependent phonon contributions in the dielectric permittivity shift dispersion of the surface polaritons in ZnGeP2 to the higher wavenumbers at 4 K. We have shown that experimental dispersion of PSP is in agreement with theory.