Growth mechanism of Ni on Pt(110) at low temperature

Ni atoms deposited on Pt(110)-(1 x 1) and(1 x 2) surfaces are studied and compared at 130 K. The Auger uptake curve of Ni on the Pt(110)-(1 x 1) surface shows an exponential-type growth. The intensities of all (1 x 1) LEED spots decrease gradually and exhibit no oscillation during the deposition. These results demonstrate that this growth follows the Volmer-Weber mode. On the other hand, the Auger uptake curve of Ni on the Pt(110)-(1 x 2) surface shows a premonolayer break with an initial linear growth, The LEED pattern changes from (1 x 2) to a pseudo-(1 x 1) after Ni atoms fill the sites of the missing rows. After that, the Auger uptake curve turns to an exponential-type and the LEED spot patterns all diminish gradually when more Ni atoms are deposited on the Pt(110)-(1 x 2) surface. These results demonstrate that the growth of Ni on the Pt(110)-(1 x 2) surface follows the Stranski-Krastanov (SK) mode. The growth mechanism is discussed by considering the lattice mismatch, diffusion, and the surface free energies of the adsorbate and the substrate.