Photoemission study of bonding at the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">CaF</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>-on-Si(111) interface

Olmstead, Marjorie A.; Uhrberg, R. I. G.; Bringans, R. D.; Bachrach, R. Z.

doi:10.1103/physrevb.35.7526

Cited by 167 publications

(41 citation statements)

References 32 publications

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“…The epitaxial relation depends on the growth temperature, the ionicity of the substrate, and the lattice matching conditions between the film and the substrate [16][17][18][19][20][21][22][23]. In the case of epitaxial growth of semiconductor on single crystal CaF 2 (1 1 1) surfaces, the semiconductor exhibited a type B orientation when the CaF 2 surface was exposed to e-beam, ion-irradiation or high temperature prior to film deposition [19,20,24,25].…”

Section: Resultsmentioning

confidence: 99%

Small angle grain boundary Ge films on biaxial CaF2/glass substrate

Gaire

Clemmer

et al. 2010

Journal of Crystal Growth

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Section: Resultsmentioning

confidence: 99%

Small angle grain boundary Ge films on biaxial CaF2/glass substrate

Gaire

Clemmer

et al. 2010

Journal of Crystal Growth

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“…Ca, 20,[30][31][32]36,37 Sr, 38 Yb, 7,8 and Eu 10-13 form a ͑2 ϫ 1͒ reconstruction, while the adsorption of Ba leads to a ͑2 ϫ 8͒ reconstruction. 25,39 The origin of this difference was proposed to be either the large ionic radius of Ba that induces a strain relaxation within the ͑2 ϫ 1͒ unit cell, 25 or the disorder of the ϫ8 periodicity caused by defects in the Ca, Sr, Yb, and Eu adsorbed surface.…”

Section: B Eu/ Si"111…-"2 ã 1…mentioning

confidence: 99%

Structural investigation of the quasi-one-dimensional reconstructions induced by Eu adsorption on a Si(111) surface

2005

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The surface structures of the ͑quasi-͒one-dimensional reconstructions induced by the adsorption of Eu on Si͑111͒ have been investigated by low-energy electron diffraction ͑LEED͒ and high-resolution core-level photoelectron spectroscopy. Different phases were observed in LEED depending on the Eu coverage. The lowest coverage phase has a ͑3 ϫ 2͒ periodicity, and the highest coverage phase has a ͑2 ϫ 1͒ one. Of the intermediate phases, the LEED pattern of the so-called ͑5 ϫ 1͒ surface indicates that this surface has actually a ͑5 ϫ 4͒ periodicity. The Eu 4f core-level spectra show that the Eu coverages of the ͑3 ϫ 2͒, ͑5 ϫ 4͒, and ͑2 ϫ 1͒ phases are 1 / 6 monolayer ͑ML͒, 0.3 ML, and 0.5 ML, respectively, and that the valence state of the adsorbate is 2+ in all these three phases. In the Si 2p core-level spectra, three surface components were observed in both the lowest and highest coverage phases. By considering the energy shift and intensity of each surface component, we conclude that the structure of the ͑3 ϫ 2͒ phase is basically the same as that of the honeycomb-chain-channel model, and that the ͑2 ϫ 1͒ phase is formed by -bonded Seiwatz Si chains. Regarding the ͑5 ϫ 4͒ phase, two extra Si 2p surface components were observed together with the three components observed in the two end phases. Taking the energy shifts and intensities of the extra surface components into account, we propose a structural model of the ͑5 ϫ 4͒ phase.

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“…It is well known, however, that CaF 2 molecules dissociate at the Si͑111͒ surface and form CaF molecules and SiF x complexes at the interface if CaF 2 is deposited at temperatures above 250°C. 3,30,31,51,52 The dissociated CaF molecules adsorb with Ca on T 4 sites and the succeeding CaF 2 film grows with B orientation ͑cf. Ref.…”

Section: ͑2͒mentioning

confidence: 99%

“…29 The formation of a CaF interface layer due to dissociation of CaF 2 at the Si͑111͒ surface and subsequent desorption of SiF x complexes has also been verified by x-ray photoelectron spectroscopy. 30,31 Furthermore, investigations by grazing incidence x-ray diffraction ͑GIXRD͒ verified both T 4 and H 3 adsorption sites for ultrathin CaF films if they are treated by rapid thermal annealing at very high temperatures after deposition. 32 While these studies on CaF submonolayers were performed under conditions of ultrahigh vacuum ͑UHV͒ the structure of ultrathin CaF 2 films has also intensively been studied ex situ by XRD with samples where the CaF 2 film was capped by a protecting amorphous Si film or where CaF 2 was even unprotected.…”

Section: Introductionmentioning

confidence: 99%

Structural transitions and relaxation processes during the epitaxial growth of ultrathinCaF2films on Si(111)

et al. 2010

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The structure and morphology of ultrathin lattice matched CaF 2 films of very few monolayers thickness, which were deposited on Si͑111͒ substrates by molecular-beam epitaxy, have been studied in situ by synchrotron based grazing incidence x-ray diffraction. Even for the thinnest investigated film of three monolayers thickness, the in-plane structure of the CaF 2 film is determined by a lateral separation in two domains: a pseudomorphic phase assuming the lateral lattice constant of the Si͑111͒ substrate and a completely relaxed phase. Analysis of the crystal truncation rods verifies that both phases adopt the entire homogeneous CaF 2 film thickness. Therefore, we propose that atomic steps of the substrate bypass the nucleation barrier for the formation of ͑Shockley partial͒ dislocations so that the film starts to relax below the classical critical film thickness. While the relaxed phase assumes also the CaF 2 bulk lattice constant for the vertical direction, the vertical lattice constant of the pseudomorphic phase increases due to the compressive lateral strain at the interface. This vertical expansion of the pseudomorphic phase, however, is larger than expected from the elastic constants of the CaF 2 bulk. The fraction of the pseudomorphic CaF 2 phase decreases with increasing film thickness. The interface between the pseudomorphic CaF 2 phase and the Si͑111͒ substrate is characterized by Ca on T 4 sites, a smaller distance between the Si͑111͒ substrate and the CaF interface layer and an expanded layer distance between CaF interface layer and the completely stoichiometric CaF 2 film.

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Photoemission study of bonding at theCaF2-on-Si(111) interface

Cited by 167 publications

References 32 publications

Small angle grain boundary Ge films on biaxial CaF2/glass substrate

Small angle grain boundary Ge films on biaxial CaF2/glass substrate

Structural investigation of the quasi-one-dimensional reconstructions induced by Eu adsorption on a Si(111) surface

Structural transitions and relaxation processes during the epitaxial growth of ultrathinCaF2films on Si(111)

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