SURFACE-INDUCED DIPOLE MOMENTS OF GALLIUM, INDIUM, AND TIN ON MOLYBDENUM SURFACE

Liquid gallium (Ga), indium (In), and tin (Sn) were deposited on a molybdenum (Mo) surface. The surface-induced dipole moments of adsorbed adatoms Ga, In, and Sn on Mo were determined experimentally using field-ion and field-emission microscopy. The procedure of the experiment consisted of measuring the change in work function of Mo due to the adsorbed adatoms. The coverage of adatoms was obtained directly from a field-ion image of the surface using a field-ion microscope. The work function changes were obtained by measuring the field-emission currents and plotting the Fowler–Nordhiem curves. The results of this experiment for the induced dipole moments of Ga, In, and Sn adatoms were found to be 2.35 (D) for Ga, 2.39 (D) for In, and 2.25 (D) for Sn. These values are in good agreement with calculations using the charge transfer theory of chemisorption.