Book/Dissertation / PhD Thesis

FZJ-2018-05692

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Creating and characterizing a single molecule device for quantitative surface science

Green, M. F. B. (Corresponding author)FZJ*

2018
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-95806-352-5

Please use a persistent id in citations: http://hdl.handle.net/2128/19762

Abstract: This thesis has presented the creation and characterization of a single molecule device. A new microscopy method, SQDM, was developed and shown to be capable of measuring local electrostatic potential in a truly quantitative fashion. The nature of the single molecule sensor itself was investigated in-depth and unexpected results were achieved, contradicting the predictions of the highly successful orthodox theory of the Coulomb blockade. The single molecule device was constructed with the use of atomically precise single molecule manipulation detailed in Chap. 2. Approaching the microscope tip towards a single molecule, a covalent bond was formed between the apex atom of the tip and one of the double-bonded corner oxygen atoms of the molecule. This bond was empirically found to be strong enough to remove the molecule not only from its chemisorbed state on the surface, but from its hydrogen-bonded molecular layer. The removals were made possible by the augmentation of the SPM setup with a three-dimensional motion tracking device, which was used to explore custom removal trajectories by selective variation. Since the molecule’s geometry was controlled throughout the manipulation process, it was thereafter possible to re-deposit the molecule to the surface by re-approaching and applying a voltage pulse. Using this protocol, the word ‘JÜLICH’ was patterned into a PTCDA monolayer by removing molecules one by one. The correction of a mistake in the patterning was also demonstrated by lowering a molecule into a previously created vacancy. Currently work is underway to further the understanding of the key parameters involved in successful removal trajectories. Next, the functionality of the single molecule device was exhibited in Chap. 3 with the development of SQDM. It was shown that the molecular QD was sufficiently electronically decoupled from the tip’s electronic states that integer charge could be stabilized on it: the presence of resonant tunnelling features as well as sudden changes in the tip-sample force were the signals of single electron charging. The [...]

Note: RWTH Aachen, Diss., 2018

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Contributing Institute(s):

1. Funktionale Nanostrukturen an Oberflächen (PGI-3)

Research Program(s):

1. 142 - Controlling Spin-Based Phenomena (POF3-142) (POF3-142)

Appears in the scientific report 2018

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