Raman study of the amorphous SiNi alloy

Raman measurements were carried out for sputtered amorphous SiNi thin films . Raman scattering in a-Si is not influenced by a low Ni content (less than or equal to 8.3 at.%) to any significant degree, the position of peaks and their widths are not changed. A shift to lower frequencies and a broadenin g of the high frequency band transverse optical (TO) (which results in a re distribution of phonon states to lower frequencies) are observed with an in crease of the Ni content. These modifications are correlated with the prese nce of Ni in the coordination sphere of Si, as resulted from the calculated local structure in Ni-Si alloys on the basis of the diffraction patterns. (C) 1998 Elsevier Science S.A. All rights reserved.