An atomic bricklaying rule during the initial growth of silver thin film on the Pt(1 1 0)-(1×2) surface
The growth of silver thin film on the Pt(1 1 0)-(1×2) surface was studied by AES and CO thermal desorption spectroscopy. At 300 K, the silver growth follows the Stranski-Krastanov mode, i.e., layer-by-layer growth up to 1.5 monolayer (ML) followed by 3D island growth. During the course of the initial 1.5 ML layer-by-layer growth, the first 0.5 ML silver atoms fill in the missing-row sites of the Pt(1 1 0)-(1×2) surface and form a pseudo Pt(1 1 0)-(1×1)-0.5 ML Pt-0.5 ML Ag surface structure, then the subsequent 0.5 ML and the last 0.5 ML silver atoms are located on the silver sites and the platinum sites of the pseudo (1×1) surface, respectively. The initial 0.5 ML silver atoms not only block the sites of Pt(1 1 0) for CO adsorption, but also inhibit the local surface restructuring of the Pt(1 1 0)-(1×2) to the Pt(1 1 0)-(1×1) induced by CO adsorption.