Functional nanoelectronic devices: single-electron transport, memristivity, and thermoelectricity in nanoscale flms using self-assembly and graphene

This dissertation reports on several experimental projects studying electronic transport in thin-flm electronic devices. Self-assembly methods and graphene were used to realise devices contacting films of self-assembled PbS quantum dots. The devices have exhibited single-electron tunnelling with a high yield. The electrical properties of the junctions are studied individually and collectively using statistical tools to extract correlations between device geometries and electrical data. The dissertation includes discussion of the theory of relevant electronic transport including numerical simulations. Several initiated projects deriving from this work are introduced. A second device reported in this thesis is a memristive switch. Contacting thin films of Al2O3 with graphene delivered junctions which exhibit memristive behaviour with an ultrahigh on-off conductance ratio. The conduction state of the junctions is correlated with morphological changes in the devices, whereby conductive flament formation in the junction is found to lead to electrically-controllable and reversible gas encapsulation in bubbles in the structure. The device is measured electrically and topographically, and the correlation between the two aspects is studied. A discussion of memristive conduction is included with numerical simulations. A third section reports on a project studying thermoelectricity in self-assembled molecular junctions, as they show potential for improved thermoelectric efficiency for energy harvesting; this is discussed in the dissertation. Strategies to benchmark the studies are presented with relevant devices fabricated and measured. These include the development of a measurement protocol to study thermoelectricity in devices, studies of electrical coupling between various molecular structures and graphene electrodes, molecular-structure dependence of electrical and thermal conductance of junctions. Preliminary results and on-going work are discussed.

Name dc:type.qualificationname

Doctor of Philosophy (PhD)

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2019

Author dc:creator

• Astier, Hippolyte Pierre Andre Georges

Advisor dc:contributor.advisor

• Ford, Christopher John Bristow

• molecular elctronics
• graphene
• devices
• nanoelectronics
• thin films
• self-assembly
• quantum dot
• thermoelectricity
• single-electron tunnelling
• single-electron tunneling
• self-assembled monolayer
• memristor
• memristivity
• nanoactuation
• semiconductor physics
• condensed matter physics
• thermoelectric
• energy harvesting
• Coulomb blockade
• Coulomb staircase
• nanocrystal

Licence

• https://www.repository.cam.ac.uk/bitstreams/60c92fb5-3afd-4d12-8eb8-963e360cb5f9/download
• https://www.rioxx.net/licenses/all-rights-reserved/

Language dc:language

en

DOI dc:identifier.doi

https://doi.org/10.17863/CAM.38857

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/291697