Differential anomalous X-ray scattering studies of amorphous In-Se

The local structure of amorphous indium selenide semiconducting films has been studied by differential anomalous X-ray scattering. Intensity measurements were carried out for two samples containing 50 and 66 at.% Se. The scattered intensities were measured using incident photon energies tuned exactly at the In and Se absorption K-edges (27,950 and 12,653 eV) and further below the edges (27,000 and 11,800 eV). The differential structure factors were calculated from two sets of the intensity data, which were then converted to real space by the Fourier transform. The obtained results show that in the investigated amorphous films each Se has three nearest-neighbours and In is tetrahedrally coordinated and suggest a certain degree of chemical disorder in which In-Se, In-In and Se-Se correlations occur.