Using surface and interface optics to probe the capping, with amorphous Si, of Au atom chains grown on vicinal Si(111)

McAlinden, Niall; McGilp, J. F.

doi:10.1088/0953-8984/21/47/474208

Cited by 9 publications

(12 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been shown previously, for the anisotropic systems, that the RAS response is very sensitive to the Au chain structure [7]. In addition, it is well known that the structure of the Si(557) and Si(775) surfaces change significantly, by faceting, both above and below the [5]).…”

Section: Copyright C Epla 2010mentioning

confidence: 95%

New evidence for the influence of step morphology on the formation of Au atomic chains on vicinal Si(111) surfaces

McAlinden

McGilp

2010

EPL

View full text Add to dashboard Cite

Gold atomic chain structures that grow on singular and vicinal Si(111) surfaces have attracted considerable interest as model systems for exploring quasi-one-dimensional metallic behaviour. The structure of the prototypical Si(111)-5 × 2-Au system remains controversial, however. Reflection anisotropy spectroscopy provides new, independent evidence supporting a recently proposed three-Au-chain structure. For stepped surfaces, the results provide good evidence that a single Au chain forms adjacent to [ 11 2] steps and a double Au chain forms adjacent to [11 2] steps. In both cases spectral lineshape and coverage data support a three-chain Si(111)-5 × 2-Au structure forming over the remainder of the terrace. For all the vicinal Si(111) surfaces, including Si(557) and Si(775), it is the step morphology, and not the terrace width, that determines whether single-or double-Au-chain structures are formed in the region of the steps.

show abstract

Section: Copyright C Epla 2010mentioning

confidence: 95%

New evidence for the influence of step morphology on the formation of Au atomic chains on vicinal Si(111) surfaces

McAlinden

McGilp

2010

EPL

View full text Add to dashboard Cite

show abstract

“…The computed RAS response of Si(557)-(5 Â 2)-Au is shown in Fig. 2(b) and compared with the available experimental data [12,38]. Like Si(111)-Au, the Si(557)-Au surface has been the subject of intensive study over the last decades, and as a result its structure is well known [2,39].…”

Section: H Y S I C a L R E V I E W L E T T E R S Week Ending 23 Augusmentioning

confidence: 99%

Optical Fingerprints of Si Honeycomb Chains and Atomic Gold Wires on the Si(111)-(5×2)-Au Surface

Hogan

Ferraro²,

McAlinden

et al. 2013

Phys. Rev. Lett.

View full text Add to dashboard Cite

The intensively studied Si(111)-(5 Â 2)-Au surface is reexamined using reflectance anisotropy spectroscopy and density functional theory simulations. We identify distinctive spectral features relating directly to local structural motifs such as Si honeycomb chains and atomic gold wires that are commonly found on Au-reconstructed vicinal Si(111) surfaces. Optical signatures of chain dimerization, responsible for the observed (Â 2) periodicity, are identified. The optical response, together with STM simulations and first-principles total-energy calculations, exclude the new structure proposed very recently based on the reflection high-energy electron diffraction technique analysis of Abukawa and Nishigaya [Phys. Rev. Lett. 110, 036102 (2013)] and provide strong support for the Si honeycomb chain with the triple Au chain model of Erwin et al. [Phys. Rev. B 80, 155409 (2009)]. This is a promising approach for screening possible models of complex anisotropic surface structures. DOI: 10.1103/PhysRevLett.111.087401 PACS numbers: 78.68.+m, 73.20.Àr, 78.20.Bh The Si(111)-(5 Â 2)-Au surface has been the subject of long and intensive experimental and theoretical study, due to its potential for applications in nanoelectronics and its prototypical nature for studying self-assembly and properties of one-dimensional quantum structures [1,2]. On the experimental side, this includes STM [3][4][5], reflection high-energy electron diffraction (RHEED) [6], LEED [7], photoemission [8][9][10], and optical spectroscopy [11,12]; theoretical works generally focus on surface energies, electronic structure, and STM simulations [13][14][15][16]. Nonetheless, its structure remains controversial. Significant inconsistencies arose when even the most promising structures, all of which feature a Si honeycomb chain [17], were compared with experimental data [5].The recalibration in 2009 [18] of the Au coverage from 0.4 monolayers (ML) to 0.6 ML prompted a reevaluation of the Si(111)-(5Â2)-Au atomic structure. In particular, an exhaustive theoretical-experimental study by Erwin-Barke-Himpsel [16] (henceforth, EBH) proposed a three-chain model that largely resolved the remaining discrepancies in the STM and photoemission data [5]. However, a recent RHEED study by Abukawa and Nishigaya [6] (henceforth, AN) predicted a completely new structure, which appears consistent with Y-shaped structures found in STM [3,5]. Most notably, the model does not contain Si honeycomb chains.Independent evaluation of competing structural models is provided by reflectance anisotropy spectroscopy (RAS) [19]. The technique probes both filled and empty surface and interface states while discriminating against the bulk response of cubic materials and hence is particularly sensitive to the local surface and interface atomic structure. Moreover, RAS simulation has now evolved to a level capable of producing impressive agreement with experiment, revealing sensitivity to subtle structural phenomena, such as dimer composition [20] [26] in interface systems. Adsorbaterecon...

show abstract

“…Recently, SXRD studies of Si(111)-5 × 2-Au, capped with 4.6 nm of amorphous Si (a-Si), showed that the positions of the Au atoms under the capping layer were essentially unchanged [18], raising the interesting possibility of successful capping of this nanowire structure with a-Si. However, RAS studies have shown that the anisotropic optical response of the (5 × 2)-Au structure is destroyed during capping, indicating that the technological interesting quasi-1D properties have been lost [19].…”

Section: Conventional Optical Techniques and Their Adaptationmentioning

confidence: 99%

“…• offcut Si(111) [19]. The conductivity of nanowires is a crucial parameter, but electrical contacting to such structures is a major problem, with the contacts often dominating the response of the system.…”

Section: Nanostructures and Solid-solid Interfacesmentioning

confidence: 99%

Probing surface and interface structure using optics

McGilp

2010

J. Phys.: Condens. Matter

Self Cite

View full text Add to dashboard Cite

Optical techniques for probing surface and interface structure are introduced and recent developments in the field are discussed. These techniques offer significant advantages over conventional surface probes: all pressure ranges of gas-condensed matter interfaces are accessible and liquid-liquid, liquid-solid and solid-solid interfaces can be probed, due to the large penetration depth of the optical radiation. Sensitivity and discrimination from the bulk are the two challenges facing optical techniques in probing surface and interface structure. Where instrumental improvements have resulted in enhanced sensitivity, conventional optical techniques can be used to characterize heterogeneous adsorbed layers on a substrate, often with sub-monolayer resolution. Nanoscale lateral resolution is possible using scanning near-field optics. A separate class of techniques, which includes reflection anisotropy spectroscopy, and nonlinear optical probes such as second-harmonic and sum-frequency generation, uses the difference in symmetry between the bulk and the surface or interface to suppress the bulk contribution. A perspective is presented of likely future developments in this rapidly expanding field.

show abstract

Using surface and interface optics to probe the capping, with amorphous Si, of Au atom chains grown on vicinal Si(111)

Cited by 9 publications

References 28 publications

New evidence for the influence of step morphology on the formation of Au atomic chains on vicinal Si(111) surfaces

New evidence for the influence of step morphology on the formation of Au atomic chains on vicinal Si(111) surfaces

Optical Fingerprints of Si Honeycomb Chains and Atomic Gold Wires on the Si(111)-(5×2)-Au Surface

Probing surface and interface structure using optics

Contact Info

Product

Resources

About