Molecular Electronics Meets Direct-Write Carbon Nanofabrication via Focused Electron-Beam-Induced Deposition (FEBID): A Platform for Junction Architecture Design

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide The electrical characteristics of a molecular junction are highly sensitive to the nature and uniformity of the molecule|electrode contacts. This gives rise to significant interest in the development of not only the active molecular structures that modulate charge transport and the anchor groups that contact them to the electrodes, but also methods for assembling uniform molecular monolayers on a substrate electrode and subsequent fabrication of a “top electrode” to achieve the reliable fabrication of viable molecular electronic devices. In this contribution, 4-(4-(4-(trimethylsilylethynyl)phenylethynyl)phenylethynyl)aniline was converted to the corresponding diazonium salt and electrografted onto highly oriented pyrolytic graphite (HOPG), resulting in an organized monolayer covalently bonded to the HOPG “substrate” electrode. Subsequently, focused electron-beam-induced deposition was used to form an amorphous carbon top electrode (C-FEBID) onto the monolayer from a naphthalene precursor. By guiding the raster scanning of the electron beam, the position, shape, and thickness of the carbon electrode “written” onto the monolayer can be controlled with nanometer precision. In addition, as a proof-of-principle demonstration of the construction of the interconnects necessary for integration of molecular devices, platinum was deposited precisely on top of the C-FEBID electrodes, using focused-ion-beam-induced deposition of PtMe 3 Cp Me (Cp Me = η 5 -C 5 H 4 Me) (Pt-FIBID). The HOPG|molecule|C-FEBID|Pt-FIBID “large area” junctions produced in this manner exhibited excellent reproducibility and were free of short circuits for top-electrode dimensions ranging from 4 × 4 to 8 × 8 μm 2 . The electrical characteristics of these devices were measured and modeled by using quantum chemical approaches. These results illustrate alternative routes toward the fabrication of planar 2D devices based on molecular monolayers and carbon electrodes.

Source: ACS Applied Electronic Materials

DOI: 10.1021/acsaelm.5c01566

Authors: Aitor García-Serrano, Sara Sangtarash, Alejandro González-Orive, Hatef Sadeghi, Santiago Martín, Lucía Herrer, Richard J. Nichols, Paul J. Low, Colin J. Lambert, José María de Teresa, Soraya Sangiao, Pilar Cea

Institutions: Consejo Superior de Investigaciones Científicas, Universidad de Zaragoza, Instituto de Nanociencia y Materiales de Aragón, University of Warwick, Lancaster University, Universidad de La Laguna, University of Liverpool, The University of Western Australia

Language: English

Topic: Molecular Junctions and Nanostructures

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,500

Funders: UK Research and Innovation, Ministerio de Economía y Competitividad, Ministerio de Ciencia e Innovación, Universidad de Zaragoza, Engineering and Physical Sciences Research Council, Australian Research Council, European Regional Development Fund, Agencia Estatal de Investigación, ARC Centre for Excellence in Convergent Bio-Nano Science and Technology

OpenAlex ID: W4415183563