A CONTACT POTENTIAL DIFFERENCE STUDY OF THE EPITAXIAL-GROWTH OF ALUMINUM ON PD(111) FILMS

[摘要] The growth of aluminum on epitaxial Pd(111) films formed on mica was investigated by the contact potential difference (CPD) method. The CPD was found to decrease smoothly, reaching a minimum of 1.32eV at 2ML Al coverage and saturating at that value, in good agreement with the work function difference between the bulk (111) surfaces. The quick saturation is indicative of an initial layer growth process. The growth data were analyzed according to the Topping depolarization model. The dipole moment and polarizability for the initial adsorption process were determined to be 0.29 D and 1.02-angstrom-3 respectively. The polarizability is an order of magnitude lower than theory. The bilayer film was analyzed, ex situ, by reflection high energy electron diffraction (RHEED). The adlayer was found to have grown with an epitaxial orientation, supporting the saturation CPD value. RHEED also showed that a 27-angstrom epitaxial aluminum surface was much rougher than the Pd(111) substrate film, suggesting that the growth mode was Stranski-Krastnov.

[发布日期] 1990-12-01

[效力级别]  Proceedings Paper