Studies of Eu- and Yb-induced Reconstructions on the Si(100) Surface

This thesis presents experimental studies of rare earth (RE) metal induced structures on Si(100) surfaces. Two divalent RE metal adsorbates, Eu and Yb, are investigated on nominally flat Si(100) and on vicinal, stepped Si(100) substrates. Several experimental methods have been applied, including scanning tunneling microscopy/spectroscopy (STM/STS), low energy electron diffraction (LEED), synchrotron radiation photoelectron spectroscopy (SR-PES), Auger electron spectroscopy (AES), thermal desorption spectroscopy (TDS), and work function change measurements (Δφ). Two stages can be distinguished in the initial growth of the RE/Si interface: the formation of a two-dimensional (2D) adsorbed layer at submonolayer coverage and the growth of a three-dimensional (3D) silicide phase at higher coverage. The 2D phase is studied for both adsorbates in order to discover whether they produce common reconstructions or reconstructions common to the other RE metals. For studies of the 3D phase Yb is chosen due to its ability to crystallize in a hexagonal AlB2 type lattice, which is the structure of RE silicide nanowires, therefore allowing for the possibility of the growth of one-dimensional (1D) wires. It is found that despite their similar electronic configuration, Eu and Yb do not form similar 2D reconstructions on Si(100). Instead, a wealth of 2D structures is observed and atomic models are proposed for the 2×3-type reconstructions. In addition, adsorbate induced modifications on surface morphology and orientational symmetry are observed. The formation of the Yb silicide phase follows the Stranski-Krastanov growth mode. Nanowires with the hexagonal lattice are observed on the flat Si(100) substrate, and moreover, an unexpectedly large variety of growth directions are revealed. On the vicinal substrate the growth of the silicide phase as 3D islands and wires depends drastically on the growth conditions. The conditions under which wires with high aspect ratio and single orientation parallel to the step edges can be formed are demonstrated.

För si sådan är kärlekens begäran

Soitinnus: mieskuoro (TTBB).

För si sådan är kärlekens begäran

Soitinnus: mieskuoro

Historisk och oeconomisk beskrifning öfwer siö-staden Nystad

Painovuosi nimekkeestä.

Si-Kla! Säsongnyhet för Automobilister!

kuv., 14 x 21 cm

Si-Kla! Ajokausi-uutuus Autoilijoille!

kuv., 14 x 21 cm

Caelator candido lectori salutem : accipe candide lector absolutissimam septentrionalium regionum, Suetiae, Gotiae, Norvegiae, Prussiae, Pomeraniae, Ducatus Megapolensis, Frisiae, Geldriae ... id si videro aliquas tibi dabo descriptiones non iniocundas vale

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Al magnifico s. Francesco Scaridino non mi parea cosa conueniente ch'io lasciasa andar fuora : l'Europa, con sa qiuta [quita] del Africa, et parte del Asia senza ch'iosse segnassi nel fronte nome honorato si onde essa non fusse isprezzata ó ...

Kartta kuuluu A. E. Nordenskiöldin kokoelmaan

De poësi Fennica 2

Invokaatio: D.A.G.

De poësi Fennica 4

Invokaatio: D.A.G.

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Invokaatio: D.A.G.

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Invokaatio: D.A:G.