Adsorption of Methyl-Substituted Benzylazide on Si(001): Reaction Channels and Final Configurations

Abstract

The reaction of a methyl-substituted benzylazide on the silicon (001) surface was investigated by means of X-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM), and density functional theory (DFT)-based computations. It was found that the reaction takes place via an intermediate state, which could be experimentally observed at low temperatures. XPS analysis showed that at temperatures of 150 K and above, the azide further reacts on the silicon surface via abstraction of N 2 . The final state sees the remaining nitrogen atom of the adsorbate binding covalently to the surface. In the STM images, this final state is associated with two different adsorption configurations. In comparison with DFT calculations, these two configurations are assigned to the molecule being bound via the nitrogen atom only and to a configuration with the molecule bound to the substrate via the nitrogen atom and carbon ring simultaneously.

Combined XPS and DFT investigation of the adsorption modes of methyl enol ether functionalized cyclooctyne on Si(001)

“…XPS measurements were performed using an Al K X‐ray source with monochromator (Omicron XM1000) and a hemispherical energy analyzer (Omicron EA125). All XPS spectra were referenced to the Si 2p 3/2 peak at 99.4 eV [23] . Voigt‐profiles were used for fitting the data; they are composed of 90 % Gaussian function and 10 % Lorentzian function.…”

“…The free energy differences at 300 K and 1 bar were then added as a higher order correction to the HSE06‐D3 energies. Scripts for extracting thermodynamic quantities form a VASP calculation have been published elsewhere [23] . We will discuss electronic energy differences and Gibbs energies of adsorption at the HSE06‐D3 level of approximation unless otherwise noted.…”

Efficient Hierarchical Models for Reactivity of Organic Layers on Semiconductor Surfaces

“…We note in passing that additional synthetic challenges such as double adsorption of bifunctional molecules are still not fully overcome. These issues are also under investigation but not further discussed in this study [19,20]. However, attachment of molecules in the second organic layer could recently be demonstrated [21].…”

Efficient Hierarchical Models for Reactivity of Organic Layers on Semiconductor Surfaces

“…We note in passing that additional synthetic challenges such as double adsorption of bifunctional molecules are still not fully overcome. These issues are also under investigation but not further discussed in this study [39,40]. However, based on the IEDDA reaction, attachment of molecules in the second organic layer could recently be demonstrated [41].…”