Dependence of photoelectron diffraction of single molecule adsorbing Ni(111) surface on the sources of Cr-Lα and Al-Kα lines

In order to elucidate the dependence of X-ray photoelectron diffraction (XPED) method on the X-ray source, we investigated XPED patterns from a h-BN/Ni(111) surface by using both Cr-Lα (572.8 eV) and Al-Kα (1486.6 eV). As the first step Ni3p photoelectron diffraction patterns were measured and calculated from a substrate Ni(111) by using both sources. Forward scattering peaks and Kikuchi-like bands were clearly observed in both experimental and theoretical patterns excited by Al-Kα. On the contrary, these features of Cr-Lα excited XPED patterns were more diffuse. This suggests that the usage of a lower energy X-ray source improves XPED structural analysis on ultrathin films composed of light elements.