Morphology of monolayer MgO films on Ag(100): switching from corrugated islands to extended flat terraces.
The ability to engineer nearly perfect ultrathin oxide layers, up to the limit of monolayer thickness, is a key issue for nanotechnological applications. Here we face the difficult and important case of ultrathin MgO films on Ag(100), for which no extended and well-ordered layers could thus far be produced in the monolayer limit. We demonstrate that their final morphology depends not only on the usual growth parameters (crystal temperature, metal flux, and oxygen partial pressure), but also on aftergrowth treatments controlling so far neglected thermodynamics constraints. We thus succeed in tuning the shape of the oxide films from irregular, nanometer-sized, monolayer-thick islands to slightly larger, perfectly squared, bilayer islands, to extended monolayers limited apparently only by substrate steps.
IMEM-CNR, UOS Genova, Via Dodecaneso 33, 16146 Genova, Italy and Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy.
Jagriti
J
Pal
IMEM-CNR, UOS Genova, Via Dodecaneso 33, 16146 Genova, Italy.
Marco
M
Smerieri
IMEM-CNR, UOS Genova, Via Dodecaneso 33, 16146 Genova, Italy and Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy.
Edvige
E
Celasco
IMEM-CNR, UOS Genova, Via Dodecaneso 33, 16146 Genova, Italy.
Letizia
L
Savio
IMEM-CNR, UOS Genova, Via Dodecaneso 33, 16146 Genova, Italy and Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy.
Luca
L
Vattuone
IMEM-CNR, UOS Genova, Via Dodecaneso 33, 16146 Genova, Italy and Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy.
Mario
M
Rocca
D008277:Magnesium Oxide / Q000737:chemistry*; D016252:Microscopy, Scanning Tunneling / Q000379:methods; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D012834:Silver / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics
D008277:Magnesium Oxide; D012834:Silver