Stacking faults and twinning in homoepitaxial thin films on Ir(111) [Elektronische Ressource] / vorgelegt von Sebastian Bleikamp

Stacking Faults and Twinningin Homoepitaxial Thin Filmson Ir(111)Inaugural-DissertationzurErlangung des Doktorgradesder Mathematisch-Naturwissenschaftlichen Fakultätder Universität zu Kölnvorgelegt vonSebastian Bleikampaus OberhausenKöln, 2010Berichterstatter: Prof. Dr. Thomas MichelyProf. Dr. Mohsen Abd-ElmeguidVorsitzenderder Prüfungskommission: Prof. Dr. Ladislav BohatýTag der mündlichen Prüfung: 12. April 2010AbstractThe growth and annealing behavior of thin Iridium films on the Ir(111)surface was studied with respect to stacking fault and twin formation bymeans of scanning tunneling microscopy (STM), low energy electron diffrac-tion (LEED) and surface X-ray diffraction (SXRD).It was found that by heterogeneous nucleation of new faults at phaseboundariesbetweenareasofregularandfaultedstacking,initialfaultedareasspread into their surrounding (proliferationeffect). Inthe process, thephaseboundary is stabilized and evolves to a persistent fault structure, and atransition from layer-by-layer growth to a defect dominated growth witha fixed length scale takes place. During this transition, the majority ofthe surface area becomes twinned. A step-influenced enhancement of thestacking fault probability initially supports the effect.By the supply of additional energy in the order of 50eV per depositedatom using ion beam assisted deposition (IBAD), stacking fault and twinformation can be effectively lifted. Various strategies of IBAD have beentested.