Photoelectrochemical Generation of Electronically Conducting Polymer-Based Hybrid Junctions on Modified Si(111) Surfaces

Abstract

Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/view/object/?id=b0d0d3ef-f5a7-4f33-9baa-56285c529743 http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/voir/objet/?id=b0d0d3ef-f5a7-4f33-9baa-56285c529743 The modification of Si(111) surfaces with Si-C linked alkyl monolayers terminated by electrochemically polymerizable di(2-thienyl)carbinol moieties has been investigated by different spectroscopic techniques including IR spectroscopy, X-ray photoelectron spectroscopy (XPS), and high-resolution electron energy loss spectroscopy (HREELS). These surfaces were prepared from the photochemical reaction of ethyl undecylenate with hydrogen-terminated Si(111), followed by the conversion of the produced terminal ester groups into the tertiary alcohol using 2-thienyllithium. Despite the steric constraints induced by the aromatic rings in the monolayer, the absolute surface coverage of the organic chains was found to be high, ca. 40%. Differential capacitance measurements revealed that the derivatization procedure introduced surface states probably due to some oxidation of the Si(111) surface occurring during the photochemical step. The photopotentiodynamical oxidation of the modified Si(111) surfaces in the presence of thiophene yielded strongly adherent and smooth conducting polythiophene films. These photoelectrogenerated hybrid polythiophene-silicon junctions were then characterized by ex situ electrical measurements (dc transport, ac impedance, and surface potential measurements). The expected diode behavior due to the formation of a Schottky barrier at the alkyl/Si(111) interface was clearly observed although the rectification was rather weak and the characteristics highly nonideal. The surface states at the silicon interface were found to play a major role in determining the electrical properties of such junctions.

Photoelectrochemical etching of silicon derivatized with an electroactive thiophene-terminated alkyl monolayer: toward a redox center-induced etching activation and anisotropy

“…The preparation and spectroscopic characterization (XPS, ATR-FTIR, HREELS) of the ester-and thiophene-terminated alkyl monolayers covalently bound to n-Si(1 1 1) (Scheme 1) have been previously described [16,19]. The reported data revealed densely packed, wellordered structures with a surface coverage in the range 0.4-0.5, very close to the theoretical limit of about 0.5 proposed by Linford et al [20].…”

Assembly of Hexamolybdenum Metallic Clusters on Silicon Surfaces

“…Atomic force microscopy (AFM) analysis of the pyridinemodified surface before anchoring of the hexamolybdenum cluster shows a structure similar to that of SiA C H T U N G T R E N N U N G (111)-H or other alkyl and w-substituted alkyl monolayer-modified surfaces, [18,[30][31][32][33][34] with atomically flat, almost defect-free terraces consisting of about 3--high steps (Figure 4). The measured rootmean-square (rms) roughness is approximately 4.0 AE 0.3 .…”

Construction of Mono- and Multimolecular Layers with Electron Transfer Mediation Function and Catalytic Activity for Hydrogen Evolution on a Hydrogen-Terminated Si(111) Surface via Si−C Bond

“…For example, a monolayer with electron transfer function on Si is very important as far as the application for molecular devices, 10 sensors, 11 photoelectrochemistry, [12][13][14][15] bioelectrochemistry, 16 and electrocatalysis [13][14][15] are concerned. Organic monolayer can be formed on Si surface via direct Si-C bond utilizing thermal, [17][18][19][20][21][22][23] photochemical, 24,25 electrochemical, [26][27][28] or catalytic reaction 28,29 or reaction with radical initiators.…”