Si/Ge heteroepitaxial dots under tensile strain are grown on nanostructured Ge substrates produced by hightemperature flash heating exploiting the spontaneous faceting of the Ge(001) surface close to the onset of surface melting. A very diverse growth mode is obtained depending on the specific atomic structure and step density of nearby surface domains with different vicinal crystallographic orientations. On highly-miscut areas of the Ge (001) substrate, the critical thickness for islanding is lowered to about 5 ML, in contrast to the 11 ML reported for the flat Ge(001) surface, while on unreconstructed (1×1) domains the growth is Volmer–Weber driven. An explanation is proposed considering the diverse relative contributions of step and surface energies on misoriented substrates. In addition, we show that the bottom-up pattern of the substrate naturally formed by thermal annealing determines a spatial correlation for the dot sites.
Persichetti, L., Fanfoni, M., Bonanni, B., De Seta, M., Di Gaspare, L., Goletti, C., et al. (2019). Islanding, growth mode and ordering in Si heteroepitaxy on Ge(001) substrates structured by thermal annealing. SURFACE SCIENCE, 683, 31-37 [10.1016/j.susc.2019.02.002].
Islanding, growth mode and ordering in Si heteroepitaxy on Ge(001) substrates structured by thermal annealing
Persichetti, L.;Fanfoni, M.;Bonanni, B.;Goletti, C.;Sgarlata, A.
2019-01-01
Abstract
Si/Ge heteroepitaxial dots under tensile strain are grown on nanostructured Ge substrates produced by hightemperature flash heating exploiting the spontaneous faceting of the Ge(001) surface close to the onset of surface melting. A very diverse growth mode is obtained depending on the specific atomic structure and step density of nearby surface domains with different vicinal crystallographic orientations. On highly-miscut areas of the Ge (001) substrate, the critical thickness for islanding is lowered to about 5 ML, in contrast to the 11 ML reported for the flat Ge(001) surface, while on unreconstructed (1×1) domains the growth is Volmer–Weber driven. An explanation is proposed considering the diverse relative contributions of step and surface energies on misoriented substrates. In addition, we show that the bottom-up pattern of the substrate naturally formed by thermal annealing determines a spatial correlation for the dot sites.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
