Theory of Defects in One-Dimensional Systems: Application to Al-Catalyzed Si Nanowires

Rurali, Riccardo; Cartoixà, Xavier

doi:10.1021/nl802847p

Cited by 65 publications

(61 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The surface substitutional as well as the adatom positions are very weak scatterers also in the conduction band. The formation energies 31 of the considered configurations yield a surface segregation energy of 0.8 eV, similarly to previous reports on doping impurities in both SiNWs ͑Refs. 32 and 33͒ and Ge nanowires 34 and in agreement with experimental results.…”

Section: Scattering Cross Section Of Metal Catalyst… Physical Review supporting

confidence: 87%

Scattering cross section of metal catalyst atoms in silicon nanowires

et al. 2010

Self Cite

View full text Add to dashboard Cite

Scattering cross section of metal catalyst atoms in silicon nanowiresMarkussen, Troels; Rurali, R.; Cartoixa, X.; Jauho, Antti-Pekka; Brandbyge, Mads A common technique to fabricate silicon nanowires is to use metal particles ͑e.g., Au, Ag, Cu, Al͒ to catalyze the growth reaction. As a consequence, the fabricated nanowires contain small concentrations of these metals as impurities. In this work we investigate the effect of the metallic impurities on the electronic transport properties of silicon nanowires. The computational method is based on ab initio density functional theory together with nonequilibrium Green's functions. From the computed transmission functions we extract a scattering cross section to characterize the scattering strength of the different metal atoms. We find that Au, Ag, and Cu impurities have very similar scattering cross sections, while Al differs from the rest. Impurities located in the center of the wires scatter significantly more than impurities close to or at the surface. The results for nanowires are compared with bulk Si scattering calculations and good agreement is found. This agreement shows that the scattering results for the ultrathin nanowires ͑which are computationally feasible͒ are not dominated by finite size or surface effects, and indicate that the results can be extended to larger and experimentally more relevant wires.

show abstract

Section: Scattering Cross Section Of Metal Catalyst… Physical Review supporting

confidence: 87%

Scattering cross section of metal catalyst atoms in silicon nanowires

et al. 2010

Self Cite

View full text Add to dashboard Cite

show abstract

“…Indeed, such a correction can only be applied in case the full dielectric tensor of the system is evaluated using computationally demanding density functional perturbation theory. 38 Fortunately, as was first noted by Hummer et al, 39 owing to the high polarizability of water, the total energy of a charged, solvated system should converge as a function of the inverse volume of the system; whereas in the absence water, the leading term scales with the inverse cell length. While our system is not fully solvated, finite size tests indicated no discernible difference in energies with growing system size and we subsequently assume this correction term to be negligible.…”

Section: Construction Of Grand Canonical Energiesmentioning

confidence: 87%

Ab Initio Electrochemistry: Exploring the Hydrogen Evolution Reaction on Carbon Nanotubes

Holmberg

Laasonen

2015

J. Phys. Chem. C

View full text Add to dashboard Cite

Density functional theory (DFT) was employed to investigate the hydrogen evolution reaction (HER) on pristine and nitrogen doped carbon nanotubes (CNTs) in acidic solution. As the reaction is an electrocatalytic surface reaction, an accurate description of HER requires performing simulations under constant electrode potential conditions. To this end, we examined HER at several electrode charges allowing us to determine grand canonical activation energies as a continuous function of electrode potential. By studying the elementary steps of HER -the Volmer, Tafel and Heyrovsky reactions -and by considering hydrogen coverage effects, we found that the Volmer-Heyrovsky mechanism is the predominant HER mechanism on CNTs with the Heyrovsky step being rate-determining. Our results indicated that CNTs are electrochemically active towards HER, which seen as a decrease in activation energies with growing electrode potential, but that the activity is lower than on platinum matching experimental data.Substitutional nitrogen doping did not improve HER activity, and further research is required to determine which nitrogen configurations contribute to the enhanced catalytic activity observed for experimental NCNTs.

show abstract

“…5 must be replaced by a tensor 37 , denotedǭ. For a monoclinic crystal such as Li 2 TiO 3 the dielectric tensor has four non-zero components, as shown below 38 :…”

Section: Fig 2 Shows the Formation Energy Of The V −4mentioning

confidence: 99%

Anisotropic charge screening and supercell size convergence of defect formation energies

2013

View full text Add to dashboard Cite

One of the main sources of error associated with the calculation of defect formation energies using plane-wave Density Functional Theory (DFT) is finite size error resulting from the use of relatively small simulation cells and periodic boundary conditions. Most widely-used methods for correcting this error, such as that of Makov and Payne, assume that the dielectric response of the material is isotropic and can be described using a scalar dielectric constant ǫ. However, this is strictly only valid for cubic crystals, and cannot work in highly-anisotropic cases. Here we introduce a variation of the technique of extrapolation based on the Madelung potential, that allows the calculation of well converged dilute limit defect formation energies in non-cubic systems with highly anisotropic dielectric properties. As an example of the implementation of this technique we study a selection of defects in the ceramic oxide Li 2 TiO 3 which is currently being considered as a lithium battery material and a breeder material for fusion reactors.

show abstract

Theory of Defects in One-Dimensional Systems: Application to Al-Catalyzed Si Nanowires

Cited by 65 publications

References 36 publications

Scattering cross section of metal catalyst atoms in silicon nanowires

Scattering cross section of metal catalyst atoms in silicon nanowires

Ab Initio Electrochemistry: Exploring the Hydrogen Evolution Reaction on Carbon Nanotubes

Anisotropic charge screening and supercell size convergence of defect formation energies

Contact Info

Product

Resources

About