Photoemission study on formation of Y-Cu intermetallic compound on Cu(100) surface

Deposition of Y on the Cu(100) surface at room temperature has been studied by X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy and work function measurement. The formation of a relatively thick mixed interface, >100 A, is observed. The Y/Cu atomic ratio of the mixed interface is found to be about 1:3 at the Y coverage of 2.0 ML. Based on the Y-Cu phase diagram we suggest that an intermetallic compound YCu3 is formed in the top layer of the interface in the range of 0.8-2.0 ML. For the coverage more than 2.0 ML, the Y atoms are stopped to diffuse into the intermetallic compound and form a yttrium layer on it. (orig.)