Disorder and compositional dependences in Urbach-Martienssen tails in amorphous (GeTe)x(Sb2Te3)1−x alloys

摘要

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 B^1/2, and average halfwidth <FWHM> of Raman bands in amorphous (GeTe)x(Sb2Te3)1−x alloys at various temperatures. Obtained results reveal the compositional trends in the influence of the disordering on the absorption processes in studied alloys.