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Kazim S, Mastrippolito D, Moras P, Jugovac M, Klimczuk T, Ali M, Ottaviano L, Gunnella R. Synchrotron radiation photoemission spectroscopy of the oxygen modified CrCl 3 surface. Phys Chem Chem Phys 2023; 25:3806-3814. [PMID: 36645158 DOI: 10.1039/d2cp04586a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We investigate the experimentally challenging CrCl3 surface by photon energy dependent photoemission (PE). The core and valence electrons after cleavage of a single crystal, either in a ultra-high vacuum (UHV) or in air, are studied by keeping the samples at 150 °C, aiming at confirming the atomic composition with respect to the expected bulk atomic structure. A common spectroscopic denominator revealed by data is the presence of a stable, but only partially ordered Cl-O-Cr surface. The electronic core levels (Cl 2p, Cr 2p and 3p), the latter ones of cumbersome component determination, allowed us to quantify the electron charge transfer to the Cr atom as a net result of this modification and the increased exchange interaction between metal and ligand atoms. In particular, the analysis of multiplet components by the CMT4XPS code evidenced the charge transfer to be favored, and similarly the reduced crystal field due to the established polarization field. Though it is often claimed that a significant amount of Cl and Cr atomic vacancies has to be included, such a possibility can be excluded on the basis of the sign and the importance of the shift in the binding energy of core level electrons. The present methodological approach can be of great impact to quantify the structure of ordered sub-oxide phases occurring in mono or bi-layer Cr trihalides.
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Affiliation(s)
- S Kazim
- School of Science and Technology Physics Section University of Camerino, Via Madonna delle Carceri 9, 62032 Camerino, MC, Italy.
| | - D Mastrippolito
- Dipartimento di Scienze Fisiche e Chimiche (DSFC), Università degli Studi dell'Aquila, Via Vetoio 10, 67100 L'Aquila, Italy
| | - P Moras
- Istituto di Struttura della Materia-CNR (ISM-CNR), S.S. 14, Km 163,5, 34149 Trieste, Italy
| | - M Jugovac
- Istituto di Struttura della Materia-CNR (ISM-CNR), S.S. 14, Km 163,5, 34149 Trieste, Italy
| | - T Klimczuk
- Faculty of Applied Physics and Mathematics, and Advanced Materials Centre, Gdansk University of Technology, ul. Narutowicza 11/12, 80-233 Gdansk, Poland
| | - M Ali
- Dipartimento di Scienze Fisiche e Chimiche (DSFC), Università degli Studi dell'Aquila, Via Vetoio 10, 67100 L'Aquila, Italy.,Department of Physics, Division of Science and Technology, University of Education Lahore, Jauharabad Campus, Pakistan
| | - L Ottaviano
- Dipartimento di Scienze Fisiche e Chimiche (DSFC), Università degli Studi dell'Aquila, Via Vetoio 10, 67100 L'Aquila, Italy.,CNR-SPIN UoS L' Aquila, Via Vetoio 10, 67100 L'Aquila, Italy
| | - R Gunnella
- School of Science and Technology Physics Section University of Camerino, Via Madonna delle Carceri 9, 62032 Camerino, MC, Italy. .,INFN-Sez. Perugia, Via Pascoli Perugia, Italy
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Kamaratos M, Sotiropoulos A, Vlachos D. Ultrathin films of Ge on the Si(100)2 × 1 surface. SURF INTERFACE ANAL 2017. [DOI: 10.1002/sia.6358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- M. Kamaratos
- Department of Physics; University of Ioannina; PO Box 1186 451 10 Ioannina Epirus Greece
| | - A.K. Sotiropoulos
- Department of Physics; University of Ioannina; PO Box 1186 451 10 Ioannina Epirus Greece
| | - D. Vlachos
- Department of Physics; University of Ioannina; PO Box 1186 451 10 Ioannina Epirus Greece
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Brehm M, Groiss H, Bauer G, Gerthsen D, Clarke R, Paltiel Y, Yacoby Y. Atomic structure and composition distribution in wetting layers and islands of germanium grown on silicon (001) substrates. NANOTECHNOLOGY 2015; 26:485702. [PMID: 26553384 DOI: 10.1088/0957-4484/26/48/485702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We present a comprehensive structural investigation of the Ge wetting layer (WL) and island growth on Si(001) substrates by a combination of AFM, high resolution transmission electron microscopy and the energy-differential coherent Bragg rod analysis (COBRA) x-ray method. By considering the influence of the initial Si surface morphology on the deposited Ge, these techniques provide quantitative information on the Ge content and its distribution, in particular within the WL which plays a crucial role in the formation of epitaxial nanostructures. In the WL, the Ge content was found to be above 80% for our growth conditions. Furthermore, from the digital analysis of high-resolution transmission electron microscope images, quantitative information on the strain relaxation is obtained, which complements the COBRA analysis of the Ge distribution and content in these nanostructures.
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Affiliation(s)
- Moritz Brehm
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, 4040 Linz, Austria
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Ohtake A, Ozeki M, Nakamura J. Strain relaxation in InAs/GaAs(111)A heteroepitaxy. PHYSICAL REVIEW LETTERS 2000; 84:4665-4668. [PMID: 10990766 DOI: 10.1103/physrevlett.84.4665] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/1999] [Indexed: 05/23/2023]
Abstract
We have studied strain-relaxation processes in InAs heteroepitaxy on GaAs(111)A using rocking-curve analysis of reflection high-energy electron diffraction. Strain relaxation in the direction parallel to the surface occurs at approximately 1.5 bilayers (BL) thickness. On the other hand, the lattice constant in the direction normal to the surface remains almost unchanged below approximately 3 BL thickness and is estimated to be approximately 3.3 A. This value, slightly larger than that of bulk GaAs (3.26 A), does not quite reach the value predicted by classical elastic theory, 3.64 A. The present result has been supported by the first-principles total-energy calculations.
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Affiliation(s)
- A Ohtake
- Joint Research Center for Atom Technology (JRCAT), Tsukuba 305-0046, Japan and and Angstrom Technology Partnership (ATP), Tsukuba 305-0046, Japan
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Qin XR, Swartzentruber BS, Lagally MG. Scanning tunneling microscopy identification of atomic-scale intermixing on Si(100) at submonolayer Ge coverages. PHYSICAL REVIEW LETTERS 2000; 84:4645-4648. [PMID: 10990761 DOI: 10.1103/physrevlett.84.4645] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2000] [Indexed: 05/23/2023]
Abstract
The positions of Ge atoms intermixed in the Si(100) surface at very low concentration are identified using empty-state imaging in scanning tunneling microscopy. A measurable degree of place exchange occurs at temperatures as low as 330 K. Contrary to earlier conclusions, good differentiation between Si atoms and Ge atoms can be achieved by proper imaging conditions.
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Affiliation(s)
- XR Qin
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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Uberuaga BP, Leskovar M, Smith AP, Jonsson H, Olmstead M. Diffusion of Ge below the Si(100) surface: theory and experiment. PHYSICAL REVIEW LETTERS 2000; 84:2441-2444. [PMID: 11018905 DOI: 10.1103/physrevlett.84.2441] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/1999] [Indexed: 05/23/2023]
Abstract
We have studied diffusion of Ge into subsurface layers of Si(100). Auger electron diffraction measurements show Ge in the fourth layer after submonolayer growth at temperatures as low as 500 degrees C. Density functional theory predictions of equilibrium Ge subsurface distributions are consistent with the measurements. We identify a surprisingly low energy pathway resulting from low interstitial formation energy in the third and fourth layers. Doping significantly affects the formation energy, suggesting that n-type doping may lead to sharper Si/Ge interfaces.
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Affiliation(s)
- BP Uberuaga
- Department of Physics, Box 351560, University of Washington, Seattle, Washington 98195-1560 and Department of Chemistry, Box 351700, University of Washington, Seattle, Washington 98195-1700, USA
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