@unpublished{MenzelYehKammleretal., author = {Menzel, Andreas and Yeh, Wang-Chi Vincent and Kammler, Martin and Hupalo, Myron and Conrad, E. H. and Tringides, Michael C.}, title = {Measurements of the kinetic barriers controlling the formation of the uniform height islands in Pb/Si(111)}, abstract = {As demonstrated with SPA-LEED and STM uniform height islands of preferred thickness form during the growth of Pb on Si(111). The islands form at temperatures T<250K and for fluxes F 1/60ML/sec which requires fast kinetics and balance between several atomic processes: diffusion towards the islands , diffusion to higher layers and preference for the atoms to remain on top of the preferred height islands. We have carried out SPA-LEED experiments to measure the barriers of the processes: we prepare an initial predominantly 5-step island height distribution and we deposit an additional 0.5ML Pb at different growth temperatures Tg to determine the transition to the next preferred height of 7-step islands (i.e. 2-step islands on top of the 5-step islands) with Spot Profile Analysis(SPA-LEED). We observe that 7-step island formation is possible above a minimum temperature Tg*=175K which indicates that the transfer of atoms from the surrounding region to the top of the islands is the main controlling process.}, language = {en} } @article{MenzelKammlerConradetal., author = {Menzel, Andreas and Kammler, Martin and Conrad, E. H. and Yeh, V. and Hupalo, Myron and Tringides, Michael C.}, title = {Kinetics measurements of Pb island growth on Si(111)}, series = {Physical Review B}, volume = {67}, journal = {Physical Review B}, number = {16}, publisher = {American Physical Society}, doi = {10.1103/PhysRevB.67.165314}, abstract = {We present the results of kinetics experiments on quantum-size-effects (QSE) Pb islands formed on Si(111). We have looked at the evolution of seven-layer Pb islands from five-layer Pb islands due to the transport of Pb atoms from the interisland region, overcoming a barrier at the island edges, and moving to the island tops. By analyzing low-energy electron-diffraction and scanning-tunneling microscopy data, we have estimated the barrier for layer formation in this system to be ∼0.32eV. This energy is much larger than that expected from QSE electronic contributions alone.}, language = {en} }