Combined ab initio and XPS Investigations of the Electronic Interactions of L–Cysteine Adsorbed on GaAs(1 0 0). Issue 13 (19th August 2016)

• Record Type: Journal Article
• Authors: Juarez, María F.; Toader, Ana M.; Negrila, Catalin; Santos, Elizabeth; Lazarescu, Valentina
• Is Part Of: ChemistrySelect. Volume 1:Issue 13(2016)
• Page Start: 3623
• Page End: 3634
• Publication Date: 2016-08-19
• Subjects: Adsorption -- DFT -- GaAs(100) -- L-cysteine -- XPS; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.201600589
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: The adsorption of L‐cysteine from ethanol solutions on GaAs(1 0 0) surfaces has been studied by XPS and density‐functional theory (DFT). XPS data reveal that the formation of the adsorbate involves preferentially the As‐sites for p‐GaAs(1 0 0) and the Ga‐sites for n‐GaAs(1 0 0). The adsorbed species show different orientations of the functional groups to the surface for the different substrates. DFT calculations performed for both Ga‐dimers and As‐dimers terminated surfaces show that the adsorption is energetically favourable on both substrates. However, the adsorption energy is more negative on top of Ga‐atoms. Here an important contribution for the stabilization of the adsorbate is the interaction of the functional groups with the surface. The parallel orientation found for the Ga‐bound species by DFT calculations is in good agreement with the shift in the binding energy of the NH2 /NH3 + species observed by XPS analysis. Abstract : The adsorption of L‐cysteine on GaAs(1 0 0) surfaces studied by XPS and density‐functional theory (DFT) reveal that the formation of the adsorbate involves preferentially the As‐sites for p‐GaAs(1 0 0) and the Ga‐sites for n‐GaAs(1 0 0). The adsorbed species are stabilized by the interaction of the functional groups with the surface.