Exafs and X-ray diffraction studies on the local structure of sputter-deposited amorphous Si xTe 1− x alloys

Abstract

Extended X-ray absorption fine structure (EXAFS) above the Te K-edge and X-ray diffraction measurements on amorphous Si x Te 1− x films ( x⋍ 0.1 1 2 -0.9 ) prepared by RF sputtering were carried out to determine the local structure of those alloys. The peak areas corresponding to TeSi and TeTe bonding shown in the Fourier-transformed EXAFS oscillation change monotonically with increasing silicon content. The first peak position of the radial distribution function obtained by X-ray diffraction measurement decreases with increasing silicon concentration. The experimental results are compared with some structural models. A random covalent network (RCN) model seems to be most acceptable for explaining the local structure of amorphous Si x Te 1- x in the high-Si concentration ( x > 0.2).