Influence of doping on the structure and optical characteristics of Ge 2 Sb 2 Te 5 amorphous films

The influence of doping on the structural and optical characteristics of Ge 2 Sb 2 Te amorphous thin films has been determined with micro‐Raman scattering spectroscopy and a variable incident angle spectroscopic ellipsometer (VASE). The measured Raman spectra revealed the existence of two overlapping bands B2 near 130 cm ‐1 and C1 near 150 cm ‐1 . The additional small features in the responses were revealed in the range less than 100 cm ‐1 . Suggest that micro‐Raman scattering spectroscopy can be used to study phase change materials through local structural information. The distinct changes in refractive index and extinction coefficient of Ge 2 Sb 2 Te amorphous films due to doping were revealed in the visible range. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)