Projects per year
Abstract
Quantum dots (QD) with electric-field-controlled charge state are promising for electronics applications, e.g., digital information storage, single-electron transistors, and quantum computing. Inorganic QDs consisting of semiconductor nanostructures or heterostructures often offer limited control on size and composition distribution as well as low potential for scalability and/or nanoscale miniaturization. Owing to their tunability and self-assembly capability, using organic molecules as building nanounits can allow for bottom-up synthesis of two-dimensional (2D) nanoarrays of QDs. However, 2D molecular self-assembly protocols are often applicable on metals surfaces, where electronic hybridization and Fermi level pinning can hinder electric-field control of the QD charge state. Here, we demonstrate the synthesis of a single-component self-assembled 2D array of molecules [9,10-dicyanoanthracene (DCA)] that exhibit electric-field-controlled spatially periodic charging on a noble metal surface, Ag(111). The charge state of DCA can be altered (between neutral and negative), depending on its adsorption site, by the local electric field induced by a scanning tunneling microscope tip. Limited metal-molecule interactions result in an effective tunneling barrier between DCA and Ag(111) that enables electric-field-induced electron population of the lowest unoccupied molecular orbital (LUMO) and, hence, charging of the molecule. Subtle site-dependent variation of the molecular adsorption height translates into a significant spatial modulation of the molecular polarizability, dielectric constant, and LUMO energy level alignment, giving rise to a spatially dependent effective molecule-surface tunneling barrier and likelihood of charging. This work offers potential for high-density 2D self-assembled nanoarrays of identical QDs whose charge states can be addressed individually with an electric field.
Original language | English |
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Pages (from-to) | 11882–11890 |
Number of pages | 9 |
Journal | ACS Nano |
Volume | 13 |
Issue number | 10 |
DOIs | |
Publication status | Published - 4 Oct 2019 |
Keywords
- density functional theory
- double-barrier tunneling junction
- low-dimensional nanostructures
- noncontact atomic force microscopy
- organic quantum dots
- scanning tunneling microscopy and spectroscopy
- supramolecular self-assembly
Projects
- 1 Finished
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ARC Centre of Excellence in Future Low-energy Electronics Technologies
Fuhrer, M. (Primary Chief Investigator (PCI)), Bao, Q. (Chief Investigator (CI)), Culcer, D. (Chief Investigator (CI)), Davis, M. (Chief Investigator (CI)), Davis, J. A. (Chief Investigator (CI)), Hamilton, A. (Chief Investigator (CI)), Helmerson, K. (Chief Investigator (CI)), Klochan, O. (Chief Investigator (CI)), Medhekar, N. (Chief Investigator (CI)), Ostrovskaya, E. A. (Chief Investigator (CI)), Parish, M. (Chief Investigator (CI)), Schiffrin, A. (Chief Investigator (CI)), Seidel, J. (Chief Investigator (CI)), Sushkov, O. (Chief Investigator (CI)), Valanoor, N. (Chief Investigator (CI)), Wang, X. (Chief Investigator (CI)), Galitskiy, V. (Partner Investigator (PI)), Gurarie, V. (Partner Investigator (PI)), Hannon, J. (Partner Investigator (PI)), Höfling, S. (Partner Investigator (PI)), Hone, J. (Partner Investigator (PI)), Rule, K. C. (Partner Investigator (PI)), Krausz, F. (Partner Investigator (PI)), Littlewood, P. (Partner Investigator (PI)), MacDonald, A. (Partner Investigator (PI)), Neto, A. (Partner Investigator (PI)), Oezyilmaz, B. (Partner Investigator (PI)), Paglione, J. (Partner Investigator (PI)), Phillips, W. (Partner Investigator (PI)), Spielman, I. (Partner Investigator (PI)), Tadich, A. (Partner Investigator (PI)), Xue, Q. (Partner Investigator (PI)), Cole, J. (Chief Investigator (CI)), Perali, A. (Partner Investigator (PI)), Neilson, D. (Partner Investigator (PI)), Sek, G. (Partner Investigator (PI)), Gaston, N. (Partner Investigator (PI)), Hodgkiss, J. M. (Partner Investigator (PI)), Tang, M. (Partner Investigator (PI)), Karel, J. (Chief Investigator (CI)), Nguyen, T.-L. (Project Manager), Adam, S. (Partner Investigator (PI)), Granville, S. (Partner Investigator (PI)), Kumar, P. V. (Chief Investigator (CI)) & Daeneke, T. (Chief Investigator (CI))
ARC - Australian Research Council, Monash University – Internal School Contribution, Monash University – Internal Department Contribution, Monash University – Internal Faculty Contribution, Monash University – Internal University Contribution, University of Wollongong, University of Queensland , Tsinghua University, University of New South Wales (UNSW), Australian National University (ANU), RMIT University, Swinburne University of Technology
29/06/17 → 28/06/24
Project: Research