The Au/Si(111)7×7 interface: Correlation between electronic and morphological properties by high-resolution electron energy-loss spectroscopy, ultraviolet photoemission spectroscopy, and transmission electron microscopy

Mathieu, G.; Contini, R.; Layet, J. M.; Mathiez, P.; Giorgio, S.

doi:10.1116/1.575449

Cited by 15 publications

(4 citation statements)

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“…This result suggests that position C is very close to the surface of the silicon substrate. It is known that a very thin silicide (Au−Si alloy) layer is formed when a gold film is grown on silicon. , Thus, the surface sites indicated by C in Figure is believed to possess a different chemical nature from the top surface of the Au film. We speculate that pores within the Au films are adsorption sites for CO L (s) rather than the top surfaces of metal particles (A and B).…”

Section: Resultsmentioning

confidence: 99%

Infrared Absorption Enhancement for CO Adsorbed on Au Films in Perchloric Acid Solutions and Effects of Surface Structure Studied by Cyclic Voltammetry, Scanning Tunneling Microscopy, and Surface-Enhanced IR Spectroscopy

et al. 1999

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The adsorption of CO on Au thin film electrodes vacuum-deposited on silicon substrate has been studied in 0.1 M perchloric acid solution by surface-enhanced infrared absorption spectroscopy (SEIRAS) with the Kretschmann attenuated-total-reflection configuration. Scanning tunneling microscopy (STM) was used to investigate the surface structures of the Au films subjected to different treatments. The IR absorption of CO adsorbed on the Au film electrodes is 20 times larger than that of CO adsorbed on bulk Au electrodes measured by reflection-absorption spectroscopy. When the Au film is subjected to flame annealing, which reorients the crystallites of the Au film and results in a highly ordered (111) surface, the enhancement factor is increased further to ca. 40. Cyclic voltammetric studies demonstrated that the highly ordered Au(111) films possess a higher electrocatalytic activity toward CO oxidation than polycrystalline Au films without flame annealing. Two different linearly bonded CO species, CO L and CO L (s), were identified on the polycrystal Au surface without flame annealing. The CO L is the predominant adsorbate that yields the IR absorption at 2110-2136 cm -1 . The CO L (s) species is a minor adsorbate and gives rise to the IR absorption at 2020-2045 cm -1 , which is assigned to CO adsorbed at specific surface sites located at boundaries of Au crystallites and very close to the surface of the silicon substrate. On the highly ordered Au(111) surface prepared by flame annealing, an additional weak band assigned to bridge-bonded CO species (CO B ) was detected at 1925-1975 cm -1 in a narrow potential range (0.0-0.4 V vs SCE). The present study puts emphasis on effects of surface structures of Au films for IR absorption enhancement and demonstrates also that the Au films prepared by vacuum evaporation is of great importance in fundamental studies as well as in electrocatalysis applications.

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Section: Resultsmentioning

confidence: 99%

Infrared Absorption Enhancement for CO Adsorbed on Au Films in Perchloric Acid Solutions and Effects of Surface Structure Studied by Cyclic Voltammetry, Scanning Tunneling Microscopy, and Surface-Enhanced IR Spectroscopy

et al. 1999

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“…4,18,19,22,24 However, the building of the Fermi energy step at ϳ0.33 ML of Au, attributed to early alloy formation, can be due to gold clustering. 23 Recent high-resolution EELS and UPS experiments also indicate the presence of pure Au clusters in the first few Au-Si layers, 20 in opposition to STM results 27 which reported a layer-by-layer growth.…”

Section: Introductionmentioning

confidence: 95%

“…In spite of the many different surface techniques which have been used to study thin Au films on Si at RT, due to the difficulty of obtaining a direct correlation between electronic and morphological properties of the system there is little agreement over the exact nature of the interface. A nonexhaustive list of the techniques used, individually or combined, includes low-energy electron diffraction ͑LEED͒, [1][2][3][4][5][6][7][8][9] Auger electron spectroscopy ͑AES͒, [2][3][4][6][7][8][10][11][12][13] MeV ion backscattering, [14][15][16][17] electron-energy-loss spectroscopy ͑EELS͒, 4,6,[8][9][10][11][12][13][14][15][16][17][18][19][20] x-ray photoelectron spectroscopy ͑XPS͒, 21 ultraviolet photoelectron spectroscopy ͑UPS͒, 20,[22][23][24][25] photoemission yield spectroscopy, 7 soft-x-ray photoelectron spectroscopy,…”

Section: Introductionmentioning

confidence: 99%

UHV high-resolution electron microscopy and chemical analysis of room-temperature Au deposition on Si(001)-2×1

et al. 1997

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Investigations of Au on Si͑001͒ have suggested that room-temperature deposition of Au on a clean Si surface results in an interfacial reaction and the formation of a gold-silicide. However, these investigations typically lack direct information about the surface morphology or the exact structure at the interface. Utilizing the capabilities of a surface chemical analysis system attached to a Hitachi UHV H-9000 microscope, a layer plus island growth mode has been observed by high-resolution electron microscopy showing multiply twinned small particles on the surface. The presence of small particles for various coverages has been correlated with the shifts seen in the Si 2 p and Au 4 f binding energies as well as the peak splitting in the Si LVV Auger transition. Our chemical data are consistent with observed shifts in the binding energies of small metal clusters deposited on various substrates, and with the published data for this surface. In addition, the results are consistent with our previous studies of Ag on Si͑001͒, and indicate the growth morphology plays a crucial role in understanding spectroscopic information as well as its correlation to the structure and chemical state of the interface and surface morphology. ͓S0163-1829͑97͒08111-3͔

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“…Beside these reports there have been a number of others published over last decades in which attempts to determine the crystallographic and electronic structures and morphology of the Au layers grown on Si have been undertaken [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47]. Among most important findings are: (i) the formation of gold silicide (AuSi) at the top of Au layer, (ii) a sharp interface between Au and Si [40], and (iii) the existence of Au crystallites with different epitaxial relationship with respect to the Si substrate [46].…”

Section: Introductionmentioning

confidence: 97%

Quantum size effect in ultrathin Au films on the Si(111) surface

Kopciuszyński

Dyniec

Krawiec

et al. 2015

Applied Surface Science

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The Au/Si(111)7×7 interface: Correlation between electronic and morphological properties by high-resolution electron energy-loss spectroscopy, ultraviolet photoemission spectroscopy, and transmission electron microscopy

Cited by 15 publications

References 0 publications

Infrared Absorption Enhancement for CO Adsorbed on Au Films in Perchloric Acid Solutions and Effects of Surface Structure Studied by Cyclic Voltammetry, Scanning Tunneling Microscopy, and Surface-Enhanced IR Spectroscopy

Infrared Absorption Enhancement for CO Adsorbed on Au Films in Perchloric Acid Solutions and Effects of Surface Structure Studied by Cyclic Voltammetry, Scanning Tunneling Microscopy, and Surface-Enhanced IR Spectroscopy

UHV high-resolution electron microscopy and chemical analysis of room-temperature Au deposition on Si(001)-2×1

Quantum size effect in ultrathin Au films on the Si(111) surface

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