Abstract: Confinement of electrons can occur in metal islands or in continuous films grown heteroepitaxially upon a substrate of a different metal or on a metallic alloy. Associated quantum size effects (QSE) can produce a significant height-dependence of the surface free energy for nanoscale thicknesses of up to 10–20 layers. This may suffice to induce height selection during film growth. Scanning STM analysis has revealed remarkable flat-topped or mesa-like island and film morphologies in various systems. We discuss in detail observations of QSE and associated film growth behavior for Pb/Cu(111), Ag/Fe(100), and Cu/fcc-Fe/Cu(100) [A/B or A/B/A], and for Ag/NiAl(110) with brief comments offered for Fe/Cu3Au(001) [A/BC binary alloys]. We also describe these issues for Ag/5-fold i-Al-Pd-Mn and Bi/5-fold i-Al-Cu-Fe [A/BCD ternary icosohedral quasicrystals]. Electronic structure theory analysis, either at the level of simple free electron gas models or more sophisticated Density Functional Theory calculations, can provide insight into the QSE-mediated thermodynamic driving force underlying height selection.
Keywords: quantum size effect; metal nanofilms; quantum islands; DFT calculations; STM; Ag/Fe; Cu/Fe/Cu; Pb/Cu; Ag/NiAl; films on quasicrystals
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Han, Y.; Ünal, B.; Jing, D.; Thiel, P.A.; Evans, J.W.; Liu, D.-J. Nanoscale “Quantum” Islands on Metal Substrates: Microscopy Studies and Electronic Structure Analyses. Materials 2010, 3, 3965-3993.
Han Y, Ünal B, Jing D, Thiel PA, Evans JW, Liu D-J. Nanoscale “Quantum” Islands on Metal Substrates: Microscopy Studies and Electronic Structure Analyses. Materials. 2010; 3(7):3965-3993.
Han, Yong; Ünal, Bariş; Jing, Dapeng; Thiel, Patricia A.; Evans, James W.; Liu, Da-Jiang. 2010. "Nanoscale “Quantum” Islands on Metal Substrates: Microscopy Studies and Electronic Structure Analyses." Materials 3, no. 7: 3965-3993.