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A theoretical study of charge confinement in quantum dots: Modelling the SnO2 charge writing process. / Owen Leyton Williams

Swansea University Author: Owen Leyton Williams

Abstract

A suite of models is constructed to facilitate the simulation of the SnO[2] charge writing process. In particular, at dimensions where the semiconductor band bending does not fully evolve, this entails the self-consistent solution of the non-linear Poisson equation and the Kohn-Sham equations at non...

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Published: 2007
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
URI: https://cronfa.swan.ac.uk/Record/cronfa42429
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spelling 2018-08-02T16:24:29.2285866 v2 42429 2018-08-02 A theoretical study of charge confinement in quantum dots: Modelling the SnO2 charge writing process. 7812be97bd7c24beb5a03d4635a5d1c9 NULL Owen Leyton Williams Owen Leyton Williams true true 2018-08-02 A suite of models is constructed to facilitate the simulation of the SnO[2] charge writing process. In particular, at dimensions where the semiconductor band bending does not fully evolve, this entails the self-consistent solution of the non-linear Poisson equation and the Kohn-Sham equations at non-zero temperature, with the charge in the occupied surface states also self-consistently reconciled with the fundamental electron density generating the confining potential. In this way, a full quantum mechanical treatment of the discrete eigenstates of the quantum dot, inclusive of electron-electron effects, is made, and a Tip-QD-Substrate tunnelling model developed. This work favourably conforms with observed experimental measurements, not only satisfying the recorded data on the ratios of surface state densities far better than existing models, but also offers a tentative explanation for some of the hitherto unsatisfactorily explained sensitivity behaviour of poly crystal line gas sensors on the decrease of the grain radii. It models the charging of a spherical 4nm radius nanocrystal well, with the calculated I-V characteristic clearly exhibiting indications of the Coulomb blockade effect in good agreement with experiment. The calculated maximum electron complement of one nanocrystal of between 81 and 87 injected electrons with a modal potential difference interval between charge transfer events of 0.065V, is in excellent concordance with the experimentally inferred population of 86 elections, charge storage events occurring at intervals of 0.07V. E-Thesis Applied physics.;Condensed matter physics. 31 12 2007 2007-12-31 COLLEGE NANME Engineering COLLEGE CODE Swansea University Doctoral Ph.D 2018-08-02T16:24:29.2285866 2018-08-02T16:24:29.2285866 Faculty of Science and Engineering School of Engineering and Applied Sciences - Uncategorised Owen Leyton Williams NULL 1 0042429-02082018162453.pdf 10798137.pdf 2018-08-02T16:24:53.7200000 Output 17169192 application/pdf E-Thesis true 2018-08-02T16:24:53.7200000 false
title A theoretical study of charge confinement in quantum dots: Modelling the SnO2 charge writing process.
spellingShingle A theoretical study of charge confinement in quantum dots: Modelling the SnO2 charge writing process.
Owen Leyton Williams
title_short A theoretical study of charge confinement in quantum dots: Modelling the SnO2 charge writing process.
title_full A theoretical study of charge confinement in quantum dots: Modelling the SnO2 charge writing process.
title_fullStr A theoretical study of charge confinement in quantum dots: Modelling the SnO2 charge writing process.
title_full_unstemmed A theoretical study of charge confinement in quantum dots: Modelling the SnO2 charge writing process.
title_sort A theoretical study of charge confinement in quantum dots: Modelling the SnO2 charge writing process.
author_id_str_mv 7812be97bd7c24beb5a03d4635a5d1c9
author_id_fullname_str_mv 7812be97bd7c24beb5a03d4635a5d1c9_***_Owen Leyton Williams
author Owen Leyton Williams
author2 Owen Leyton Williams
format E-Thesis
publishDate 2007
institution Swansea University
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Engineering and Applied Sciences - Uncategorised{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Engineering and Applied Sciences - Uncategorised
document_store_str 1
active_str 0
description A suite of models is constructed to facilitate the simulation of the SnO[2] charge writing process. In particular, at dimensions where the semiconductor band bending does not fully evolve, this entails the self-consistent solution of the non-linear Poisson equation and the Kohn-Sham equations at non-zero temperature, with the charge in the occupied surface states also self-consistently reconciled with the fundamental electron density generating the confining potential. In this way, a full quantum mechanical treatment of the discrete eigenstates of the quantum dot, inclusive of electron-electron effects, is made, and a Tip-QD-Substrate tunnelling model developed. This work favourably conforms with observed experimental measurements, not only satisfying the recorded data on the ratios of surface state densities far better than existing models, but also offers a tentative explanation for some of the hitherto unsatisfactorily explained sensitivity behaviour of poly crystal line gas sensors on the decrease of the grain radii. It models the charging of a spherical 4nm radius nanocrystal well, with the calculated I-V characteristic clearly exhibiting indications of the Coulomb blockade effect in good agreement with experiment. The calculated maximum electron complement of one nanocrystal of between 81 and 87 injected electrons with a modal potential difference interval between charge transfer events of 0.065V, is in excellent concordance with the experimentally inferred population of 86 elections, charge storage events occurring at intervals of 0.07V.
published_date 2007-12-31T03:52:57Z
_version_ 1763752623177990144
score 11.013148

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