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d'Acapito F, Torrengo S, Xenogiannopoulou E, Tsipas P, Marquez Velasco J, Tsoutsou D, Dimoulas A. Evidence for Germanene growth on epitaxial hexagonal (h)-AlN on Ag(1 1 1). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:045002. [PMID: 26751008 DOI: 10.1088/0953-8984/28/4/045002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this work, a structural analysis of Ge layers deposited by molecular beam epitaxy (MBE) on Ag(1 1 1) surfaces with and without an AlN buffer layer have been investigated by x-ray Absorption Spectroscopy (XAS) at the Ge-K edge. For the Ge layers deposited on h-AlN buffer layer on Ag(1 1 1) an interatomic Ge-Ge distance [Formula: see text] Å is found, typical of 2-Dimensional Ge layers and in agreement with the theoretical predictions for free standing low-buckled Germanene presented in literature. First principles calculations, performed in the density functional theory (DFT) framework, supported the experimental RHEED and XAS findings, providing evidence for the epitaxial 2-D Ge layer formation on h-AlN/Ag(1 1 1) template.
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Affiliation(s)
- F d'Acapito
- CNR-IOM-OGG c/o European Synchrotron Radiation Facility, 71 Avenue des Martyrs, F-38043 Grenoble, France
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Zhang J, Fryauf DM, Garrett M, Logeeswaran VJ, Sawabe A, Islam MS, Kobayashi NP. Phenomenological Model of the Growth of Ultrasmooth Silver Thin Films Deposited with a Germanium Nucleation Layer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:7852-9. [PMID: 26126182 DOI: 10.1021/acs.langmuir.5b01244] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The structural properties of optically thin (15 nm) silver (Ag) films deposited on SiO2/Si(100) substrates with a germanium (Ge) nucleation layer were studied. The morphological and crystallographical characteristics of Ag thin films with different Ge nucleation layer thicknesses were assessed by cross-sectional transmission electron microscopy (XTEM), reflection high-energy electron diffraction (RHEED), X-ray diffractometry (XRD), grazing incidence X-ray diffractometry (GIXRD), X-ray reflection (XRR), and Fourier transform infrared spectroscopy (FTIR). The surface roughness of Ag thin films was found to decrease significantly by inserting a Ge nucleation layer with a thickness in the range of 1 to 2 nm (i.e., smoothing mode). However, as the Ge nucleation layer thickness increased beyond 2 nm, the surface roughness increased concomitantly (i.e., roughing mode). For the smoothing mode, the role of the Ge nucleation layer in the Ag film deposition is discussed by invoking the surface energy of Ge, the bond dissociation energy of Ag-Ge, and the deposition mechanisms of Ag thin films on a given characteristic Ge nucleation layer. Additionally, Ge island formation, the precipitation of Ge from Ag-Ge alloys, and the penetration of Ge into SiO2 are suggested for the roughing mode. This demonstration of ultrasmooth Ag thin films would offer an advantageous material platform with scalability for applications such as optics, plasmonics, and photonics.
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Affiliation(s)
- Junce Zhang
- †Jack Baskin School of Engineering, University of California at Santa Cruz, Santa Cruz, California 95064, United States
- ‡Nanostructured Energy Conversion Technology and Research (NECTAR), Advanced Studies Laboratories, NASA Ames Research Center, Moffett Field, California 94035, United States
| | - David M Fryauf
- †Jack Baskin School of Engineering, University of California at Santa Cruz, Santa Cruz, California 95064, United States
- ‡Nanostructured Energy Conversion Technology and Research (NECTAR), Advanced Studies Laboratories, NASA Ames Research Center, Moffett Field, California 94035, United States
| | - Matthew Garrett
- †Jack Baskin School of Engineering, University of California at Santa Cruz, Santa Cruz, California 95064, United States
- ‡Nanostructured Energy Conversion Technology and Research (NECTAR), Advanced Studies Laboratories, NASA Ames Research Center, Moffett Field, California 94035, United States
| | | | - Atsuhito Sawabe
- ∥Department of Electrical Engineering and Electronics, College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa 252-5258, Japan
| | | | - Nobuhiko P Kobayashi
- †Jack Baskin School of Engineering, University of California at Santa Cruz, Santa Cruz, California 95064, United States
- ‡Nanostructured Energy Conversion Technology and Research (NECTAR), Advanced Studies Laboratories, NASA Ames Research Center, Moffett Field, California 94035, United States
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Konno TJ, Sinclair R. Metal-mediated crystallization of amorphous germanium in germanium-silver layered systems. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/01418639508240305] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Toyohiko J. Konno
- a Department of Materials Science and Engineering , Stanford University , Stanford , California , 94305 , USA
| | - Robert Sinclair
- a Department of Materials Science and Engineering , Stanford University , Stanford , California , 94305 , USA
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