Ultra‐High Vacuum Deposition of Pyrene Molecules on Metal Surfaces. Issue 10 (9th September 2018)

• Record Type: Journal Article
• Authors: Schleicher, Sebastian; Borca, Bogdana; Rawson, Jeff; Matthes, Frank; Bürgler, Daniel E.; Kögerler, Paul; Schneider, Claus M.
• Is Part Of: Physica status solidi. Volume 255:Issue 10(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-09-09
• Subjects: aromatic molecules -- molecular adsorption -- scanning tunneling microscopy -- sublimation procedure; Solid state physics -- Periodicals; Solids -- Periodicals; Atomic structure -- Periodicals; 530.41
• DOI: 10.1002/pssb.201800235
• Languages: English
• ISSNs: 0370-1972

Abstract

Abstract : Interfacial properties of organic adsorbates featuring aromatic π ‐orbitals on metal surfaces play an important role for organic electronics and spintronics. Pyrene is a flat aromatic molecule with a size between ultimately small benzene and extended graphene segments. The deposition of pyrene molecules onto clean and reactive surfaces with a sub‐monolayer coverage under ultra‐high vacuum (UHV) conditions is challenging, since pyrene is a solid with a high vapor pressure. Here, a sublimation procedure under UHV and image pyrene adlayers on in situ prepared Au(111) and Fe/W(110) substrates by means of low‐temperature scanning tunneling microscopy is presented. For Au(111), the molecule–surface interaction is weak as indicated by the specific herringbone reconstruction of the Au(111) surface that is visible through the self‐assembled pyrene adlayer. Pyrene desorption due to weak intermolecular interaction self‐limits the growth to one monolayer (ML). On the more reactive 2–4 ML thick Fe films on W(110), the molecular order of the pyrene adlayer sensitively depends on the Fe thickness‐dependent dislocation pattern at the substrate surface. Irregular arrangements occur for 1 ML Fe and near substrate dislocations for 2–4 ML Fe. Self‐assembled ordered arrays form predominantly for 2 ML Fe, where the dislocation pattern leaves sufficiently large unperturbed areas between the dislocation lines. Abstract : Pyrene on Fe surfaces is an interesting model system to study spin‐dependent hybridization effects relevant for molecular spintronics. However, the high vapor pressure complicates pyrene deposition in ultra‐high vacuum (UHV) required for reactive metal surfaces. Here, an UHV sublimation procedure is presented and resulting pyrene adlayers on Au(111) and Fe/W(110) substrates are characterized by scanning tunneling microscopy.