Surface morphology and growth of AgBr on Ag(111).

Abstract

Angle-resolved photoemission with synchrotron radiation has been used to probe the surface morphologies of AgBr deposited by molecular-beam epitaxy onto Ag(111), as a function of coverage and substrate temperature. Depositions performed at 130 \ifmmode^\circ\else\textdegree\fi{}C yield results consistent with a Stranski-Krastanov (SK) growth, whereas surfaces prepared at liquid-nitrogen temperatures exhibit a more nearly layer-by-layer growth. These interpretations are supported by core-level and valence-band studies, which probed the binding energies and intensities of the Br 3d core level and the Ag(111) surface state. Low-energy electron diffraction observations show the initial SK layer to have a (\ensuremath{\surd}3 \ifmmode\times\else\texttimes\fi{} \ensuremath{\surd}3 )R30\ifmmode^\circ\else\textdegree\fi{} structure, while heavier depositions exhibit indications of AgBr(111) islands. Cold depositions show no long-range order. Surface morphology changes induced by warming a cold deposition were also studied.