The origin of inter-dimer-row correlated adsorption for NH3 on Si(001)

Owen, James H. G.; Bowler, David R.

doi:10.1016/j.susc.2009.07.042

Cited by 2 publications

(2 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There have been many scanning tunneling microscopy (STM) studies and density functional theory (DFT) calculations modeling the chemisorption of NH 3 on the bare Si(100)-2×1 surface, but there is a lack of work investigating how NH 3 interacts with H-terminated Si(100) surfaces. Recent work has looked at interactions between gas phase NH 3 molecules and ideal Si(100)-2×1 surfaces terminated with dissociatively chemisorbed ammonia (H–Si–Si–NH 2 ), including experimental evidence for hydrogen bonding between the physisorbed and chemisorbed NH 3 . , DFT calculations have put the adsorption energy for NH 3 on a primary amine (Si–NH 2 ) at ∼0.3 eV (2.0 Å bond length) and at ∼0.09 eV (2.8 Å bond length) for NH 3 on a hydride (Si–H) adjacent to a primary amine . For this reason, the population of physisorbed NH 3 should be expected to increase as the population of surface amines increases.…”

Section: Discussionmentioning

confidence: 99%

“…Recent work has looked at interactions between gas phase NH 3 molecules and ideal Si(100)-2×1 surfaces terminated with dissociatively chemisorbed ammonia (H−Si−Si−NH 2 ), including experimental evidence for hydrogen bonding between the physisorbed and chemisorbed NH 3 . 49,50 DFT calculations have put the adsorption energy for NH 3 on a primary amine (Si− NH 2 ) at ∼0.3 eV (2.0 Å bond length) and at ∼0.09 eV (2.8 Å bond length) for NH 3 on a hydride (Si−H) adjacent to a primary amine. 46 For this reason, the population of physisorbed NH 3 should be expected to increase as the population of surface amines increases.…”

Section: The Journal Of Physical Chemistry Amentioning

confidence: 99%

See 1 more Smart Citation

Ammonia Photodissociation Promoted by Si(100)

Finstad

Muscat

2014

J. Phys. Chem. A

View full text Add to dashboard Cite

Using in situ X-ray photoelectron spectroscopy measurements after reaction, we show that hydrogen-terminated Si(100) perturbs the bonding of physisorbed NH3 enabling a photochemical decomposition pathway at wavelengths different from those characteristic of either the molecule in the gas phase or the semiconductor bandgap. UV illumination only of gas phase NH3 at partial pressures from 0.1 to 100 Torr produced a maximum at 10 Torr in the N surface coverage. This is in good agreement with a model of the radical production rate showing that at this pressure the gas density balances the flux of photons at the surface with energies sufficient to dissociate NH3. UV illumination of both the gas phase and the surface produced a monotonic increase in the N coverage with pressure as well as coverages that were 3-10 times higher than when only the gas phase was illuminated. The amine saturation coverage scaled with the UV fluence at 10 Torr and 75 °C, reaching 6.9 × 10(14) atoms/cm(2) (∼1 N atom per Si surface atom) at 19 mW/cm(2) and 12 × 10(14) atoms/cm(2) (∼1.8 N per Si) at 35 mW/cm(2). Monochromatic illumination showed that the wavelengths driving deposition were not correlated with the Si bandgap, but instead were roughly the same as gas phase photodissociation (λ < 220 nm). The primary driving force to replace the hydrogen termination with amine groups was direct photodissociation of NH3 molecules whose electronic structure was perturbed by interaction with the surface. Amine groups enhanced the surface reaction of water present as a contaminant in the source gas. These results show that molecules in weakly bound surface states can have a dramatic impact on the photochemistry.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: The Journal Of Physical Chemistry Amentioning

confidence: 99%

Ammonia Photodissociation Promoted by Si(100)

Finstad

Muscat

2014

J. Phys. Chem. A

View full text Add to dashboard Cite

show abstract

Competing interactions in molecular adsorption: NH₃on Si(001)

Owen

2009

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Ammonia is a good model system for the study of co-adsorption interactions, including indirect effects such as charge and strain-induced local effects on adsorption sites, and direct interactions such as hydrogen bonding. On the Si(001) surface, it adsorbs molecularly, via a dative bond from the N atom to the down atom of a buckled dimer, and is therefore very sensitive to the local charge conditions. It will then dissociate into -H and -NH(2) groups, adsorbed on the dangling bonds of the Si dimers. The NH(2) groups do not diffuse, so any correlations deriving from interactions during adsorption are preserved, and can be derived by analysis of the arrangements of the NH(2) groups. Hydrogen-bonding interactions are crucial in understanding the behaviour of this system, with significant co-adsorption interactions occurring both along and across rows, outweighing the electrostatic or buckling-related effects. In recent years, there have been several scanning tunnelling microscopy studies and extensive computational modelling of the NH(3) on Si(001) system, attempting to determine a dominant mechanism governing co-adsorption effects. In this review, I will discuss both experimental and theoretical results, make a comparison with similar molecules such as phosphine (PH(3)), and review the different ways in which experimentalists and modellers have approached this complex system.

show abstract

The origin of inter-dimer-row correlated adsorption for NH3 on Si(001)

Cited by 2 publications

References 19 publications

Ammonia Photodissociation Promoted by Si(100)

Ammonia Photodissociation Promoted by Si(100)

Competing interactions in molecular adsorption: NH₃on Si(001)

Contact Info

Product

Resources

About

The origin of inter-dimer-row correlated adsorption for NH3 on Si(001)

Cited by 2 publications

References 19 publications

Ammonia Photodissociation Promoted by Si(100)

Ammonia Photodissociation Promoted by Si(100)

Competing interactions in molecular adsorption: NH3on Si(001)

Contact Info

Product

Resources

About

Competing interactions in molecular adsorption: NH₃on Si(001)