eprintid: 10093042 rev_number: 26 eprint_status: archive userid: 608 dir: disk0/10/09/30/42 datestamp: 2020-05-15 07:54:32 lastmod: 2021-04-01 06:10:34 status_changed: 2020-05-15 07:54:32 type: thesis metadata_visibility: show creators_name: Poulton, J.T.L. title: A Density Functional Theory Study on the properties of Dopants in Silicon Nanostructures ispublished: unpub divisions: UCL divisions: A01 divisions: B04 divisions: C06 divisions: F60 note: Copyright © The Author 2020. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. abstract: Advances in experimental techniques over the last decade have resulted in the realisation ofatomically precise doping of silicon and the creation of single dopant devices. Therefore, a greater theoretical understanding of deep dopant structures and the resulting defect complexes are required. In this thesis, we apply a variety of computational methods based on density functional theory (DFT) to the study of dopants and defect centres in bulk silicon and silicon nanostructures. The calculations are performed using the plane wave based code VASP and the linear scaling code CONQUEST. Firstly, we discuss the effects of self-compensation in p-type doped bulk silicon in the casestudy of single aluminium dopants and aluminium dopant pairs in bulk silicon. We consider the formation of dimer type complexes and determine whether such complexes will be electrically active. We then investigate the formation of dopant vacancy pairings in silicon using bismuth dopants, which are not commonly used in the semiconductor industry but may be used tofabricate solotronic devices or for quantum information processing type applications. TheDFT simulations performed are compared with experimental data.The incorporation of phosphorus in silicon is also studied within this by analysing phosphorus delta-doped layers. The effects of dopant depth and the diffusion of delta-doped layers upon the electronic structure are presented. Furthermore, this thesis includes some developmental work attempting to improve upon the efficiency multi-site support functions when used in conjunction with the linear scaling methods within the Conquest code. date: 2020-03-28 date_type: published oa_status: green full_text_type: other thesis_class: doctoral_open thesis_award: Ph.D language: eng thesis_view: UCL_Thesis primo: open primo_central: open_green verified: verified_manual elements_id: 1770031 lyricists_name: Bowler, David lyricists_name: Poulton, Jack lyricists_id: DBOWL76 lyricists_id: JPOUL62 actors_name: Poulton, Jack actors_id: JPOUL62 actors_role: owner full_text_status: public pages: 151 event_title: UCL institution: UCL (University College London) department: Physics & Astronomy thesis_type: Doctoral editors_name: Bowler, D citation: Poulton, J.T.L.; (2020) A Density Functional Theory Study on the properties of Dopants in Silicon Nanostructures. Doctoral thesis (Ph.D), UCL (University College London). Green open access document_url: https://discovery-pp.ucl.ac.uk/id/eprint/10093042/1/Thesis_jtlp-final.pdf