title: Fabrication of Metal-Insulator-Metal assemblies for spintronic devices using self-assembled monolayers
creator: Chesneau, Frédérick
subject: ddc-540
subject: 540 Chemistry and allied sciences
description: New, efficient and reproducible methods for the fabrication of Metal-Insulator-Metal (MIM) junctions for applications in spintronic devices have been developed. The junctions consisted of a gold substrate as bottom contact, p-terphenyl-based self-assembled monolayers (SAMs) as insulator layer, and thin ferromagnetic metal films (nickel) as top contact. Both pristine and electron irradiated (denoted by the prefix CL-) SAMs of [1,1’:4’,1”-terphenyl]-4,4”-dimethanethiol (TPDMT), (4’-(pyridin-4-yl)biphenyl-4-yl)alkanethiol (PPPn, n = 1,3) and perfluoroterphenyl-substituted alkanethiols (FTPn, n = 2,3) on Au(111) were used as test systems. All molecules were found to form well-ordered, high quality SAMs, a prerequisite for the fabrication of SAM-based MIM devices. In addition, the influence of the SAMs’ molecular architecture on its transport properties has been investigated. In particular, we have studied the effect of the small alkane linker (between the head group and the p-terphenyl backbone) found in all the molecules used in this work. The alkane linker was found act as an insulator, allowing us to decouple of the aromatic core’s electronic system from the substrate. We then studied the effects of electron irradiation on PPPn/Au and FTPn/Au SAMs. Both SAMs were modified with electrons. In particular, the charge transport properties of the FTPn/Au surface could be fine-tuned simply by controlling the irradiation dose. Finally, nickel was deposited on all SAMs to test their usefulness as dielectric layers in MIM devices. Whereas nickel was found, by XPS and NEXAFS spectroscopy, to penetrate into and through the SAMs of TPDMT, CL-TPDMT, PPP1 and CL-PPP1 on Au(111), a single layer of palladium chloride, deposited from solution on either TPDMT/Au or CL-PPPn/Au, promoted the nucleation and growth of nickel thin films on top of the respective SAMs via alloying of nickel with palladium. Furthermore, reaction of nickel with the perfluorinated FTPn SAMs yielded a new class of organometallic thin films in which nickel was found to reside mainly at the top. Irradiation of the FTPn monolayers with electrons gave us precise control over the work function of the CL-FPTn/Au surfaces (a crucial parameter for the fabrication of nanoelectronic devices) while favouring the nucleation and growth of top ferromagnetic contacts. The penetration of nickel into and through CL-FTPn/Au SAMs was found to decrease by as much as 30 % at high irradiation doses (> 30 mC/cm2) making FTPn systems attractive as dielectric layers for nano junctions.
date: 2011
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/12269/1/thes-full-biblio.pdf
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/12269/2/thes-full-errata.pdf
identifier: DOI:10.11588/heidok.00012269
identifier: urn:nbn:de:bsz:16-opus-122698
identifier:   Chesneau, Frédérick  (2011) Fabrication of Metal-Insulator-Metal assemblies for spintronic devices using self-assembled monolayers.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/12269/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng