Initial stages of metal encapsulation during epitaxial growth studied by STM: Rh/Ag(100)

Chang, Shinn‐Liang; Wen, Jianming; Thiel, Patricia A.; Günther, Sebastian; Meyer, J.; Behm, R. J.

doi:10.1103/physrevb.53.13747

Cited by 46 publications

(30 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1(f)]. Moreover, in contrast to adatoms on Ag surfaces (e.g., Ru/Ag(100) [12], Cu/Ag(111) [13], Cu/Ag(100) [14]), these depressions are immobile at room temperature. These observations suggests that each depression corresponds to one Cu atom alloyed into the Ag surface layer.…”

Section: Resultsmentioning

confidence: 95%

Dependence of alloying and island composition on terrace width: Growth of Cu on Ag(100)

2015

View full text Add to dashboard Cite

The growth of Cu on Ag(100) is investigated by low-temperature scanning tunneling microscopy. Exchange diffusion of Cu deposited onto Ag(100) leads to small pure Cu islands and larger islands consisting of a CuAg alloy in room temperature growth. The ratio of the different types of islands depends on terrace widths up to 100 nm. This surprisingly long-range dependence is correlated to the density of the surface alloy. We thus reveal that the exchange diffusion barrier is influenced by terrace widths far beyond quantum size confinement.

show abstract

Section: Resultsmentioning

confidence: 95%

Dependence of alloying and island composition on terrace width: Growth of Cu on Ag(100)

2015

View full text Add to dashboard Cite

show abstract

“…These include sandwichlike growth where atoms from a low surface-energy substrate climb on top of the overlayer. [2][3][4] Other possibilities of more relevance in this study include the development of bilayer islands on single-element metal substrates [4][5][6][7][8] and on alloy substrates. [9][10][11] The development of flat-topped or mesalike multilayer islands has also been observed on single-element metal substrates [12][13][14][15][16] and on alloys.…”

Section: Introductionmentioning

confidence: 99%

Formation and coarsening of Ag(110) bilayer islands on NiAl(110): STM analysis and atomistic lattice-gas modeling

et al. 2010

Self Cite

View full text Add to dashboard Cite

Scanning tunneling microscopy analysis of the initial stages of film growth during deposition of Ag on NiAl(110) reveals facile formation of bilayer Ag(110) islands at temperatures of 130 K and above. Annealing subsequent to deposition at 130 K induces coarsening of the bilayer island distribution. The thermodynamic driving force for bilayer island formation reflects a lower relative surface energy for films of even layer thicknesses. This feature derives from quantum size effects due to electron confinement in the Ag film. The kinetics of island formation and relaxation is controlled by terrace and edge-diffusion barriers, detachment barriers, interlayer diffusion barriers, and layer-dependent adsorption and interaction energies. These key energies are determined from density-functional theory analysis and incorporated into an atomistic lattice-gas model for homogeneous island formation, where specification of the adatom hop rates is consistent with detailed balance. Model analysis via kinetic Monte Carlo simulation elucidates the role of strongly anisotropic interactions in development during deposition of elongated island growth shapes and also in facilitating upward mass transport needed for bilayer island formation. The model succeeds in recovering island densities at lower temperatures but experimental densities exceed model predictions at higher temperatures plausibly due to heterogeneous nucleation at surface defects. The same model successfully describes postdeposition coarsening of small islands grown at 130 K. Scanning tunneling microscopy analysis of the initial stages of film growth during deposition of Ag on NiAl͑110͒ reveals facile formation of bilayer Ag͑110͒ islands at temperatures of 130 K and above. Annealing subsequent to deposition at 130 K induces coarsening of the bilayer island distribution. The thermodynamic driving force for bilayer island formation reflects a lower relative surface energy for films of even layer thicknesses. This feature derives from quantum size effects due to electron confinement in the Ag film. The kinetics of island formation and relaxation is controlled by terrace and edge-diffusion barriers, detachment barriers, interlayer diffusion barriers, and layer-dependent adsorption and interaction energies. These key energies are determined from density-functional theory analysis and incorporated into an atomistic lattice-gas model for homogeneous island formation, where specification of the adatom hop rates is consistent with detailed balance. Model analysis via kinetic Monte Carlo simulation elucidates the role of strongly anisotropic interactions in development during deposition of elongated island growth shapes and also in facilitating upward mass transport needed for bilayer island formation. The model succeeds in recovering island densities at lower temperatures but experimental densities exceed model predictions at higher temperatures plausibly due to heterogeneous nucleation at surface defects. The same model successfully describes postdeposition coarsenin...

show abstract

“…This process is initiated by the exchange of adatoms with atoms in the surface layer, either upon deposition ("ballistic exchange") [25] or, predominantly, as an activated step, competing with surface migration [26]. In the latter case growth follows the normal "nucleation and growth" pattern at lower temperatures, whereas above a critical temperature adatom-surface exchange sets in, which in addition to creating mixed surface layers may affect the growth behavior in various ways [26][27][28]. The critical temperature depends on the activation barrier for exchange and reaches from far below room temperature, as observed, e.g., for Ni/Ag(100) [29] or Rh/Ag(100) [28], up to temperatures well above 1000 K, as found for Pt/Ru(0001) [30].…”

Section: Preparation Of Bimetallic Surfaces By Epitaxial Growthmentioning

confidence: 99%

“…In the latter case growth follows the normal "nucleation and growth" pattern at lower temperatures, whereas above a critical temperature adatom-surface exchange sets in, which in addition to creating mixed surface layers may affect the growth behavior in various ways [26][27][28]. The critical temperature depends on the activation barrier for exchange and reaches from far below room temperature, as observed, e.g., for Ni/Ag(100) [29] or Rh/Ag(100) [28], up to temperatures well above 1000 K, as found for Pt/Ru(0001) [30]. Furthermore, it had been shown that specific sites on the surface such as deposit island edges or substrate steps may be preferred sites for exchange to occur [31].…”

Section: Preparation Of Bimetallic Surfaces By Epitaxial Growthmentioning

confidence: 99%

Spatially Resolved Chemistry on Bimetallic Surfaces

Behm

1998

Acta Phys. Pol. A

View full text Add to dashboard Cite

The local chemical properties of bimetallic surfaces, which are often drastically different from those of each of the components, will be discussed. Using CO adsorption as a probe molecule it will be shown for two model systems, Au/Pd(111) and Pt/Ru(0001), that their chemical properties depend decisively on the local surface structure and that the correct interpretation of area integrating spectroscopic and kinetic data obtained from such surfaces requires detailed knowledge of their (defect) structure and of the distribution of the different components in the surface layer. It will further be shown that information on the local chemical properties of specific structural elements such as monolayer islands and monolayer island edges, and specific surface ensembles can be gained by applying high resolution scanning tunneling microscopy imaging and area integrating spectroscopic techniques in combination to bimetallic surfaces whose morphology and composition is varied in a systematic and controlled way. Based on experimental results adsorption on a monolayer Α / substrate B system is suggested as a model for gaining information on the modifications in chemical properties of ΑB alloy surfaces due to metal-metal interactions.

show abstract

Initial stages of metal encapsulation during epitaxial growth studied by STM: Rh/Ag(100)

Cited by 46 publications

References 23 publications

Dependence of alloying and island composition on terrace width: Growth of Cu on Ag(100)

Dependence of alloying and island composition on terrace width: Growth of Cu on Ag(100)

Formation and coarsening of Ag(110) bilayer islands on NiAl(110): STM analysis and atomistic lattice-gas modeling

Spatially Resolved Chemistry on Bimetallic Surfaces

Contact Info

Product

Resources

About