Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.752838
Title: Surface modification and electronic structure characterisation of carbon-based and iron-based materials
Author: Hu, Di
ISNI:       0000 0004 7425 9496
Awarding Body: Aberystwyth University
Current Institution: Aberystwyth University
Date of Award: 2017
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Abstract:
This thesis provides an important basis for understanding the surface modulation mechanism and electronic structure variation on semiconducting surfaces and metallic thin films. The use of real-time photoelectron spectroscopy (REES) makes it possible to monitor the solid surfaces during in situ processing. The surfaces that have been investigated were (100) facet boron-doped diamond surfaces and iron thin films. The surface processing treatments include annealing, thin film coating and exposure to oxygen and hydrogen microwave plasma sources. The oxygen-terminated (100) facet diamond was annealed up to 1000°C while monitoring with REES. The oxygen desorption process on the surface can be divided into four distinct stages according the oxygen concentration on the diamond (100) surface during the heating cycle. The ratio of ketone/ether groups has been investigated. Moreover, the true band bending on O-terminated (100) has been investigated with real-time characterization, which has a maximum difference of +1.0 eV comparing with the room temperature XPS spectra data. Fluorouracil (5-FU), as a drug widely used in leukaemia and bowel cancer treatment, which is demonstrated to degrade on silver coated catheter surfaces, producing hydrofluoric acid and therefor leading to adverse effects on patients. In order to compare diamond as coating material, the adsorption of 5-FU on the oxygen and hydrogen terminated diamond (100) surfaces has been studied with x-ray photoelectron spectroscopy (XPS), showing extremely different behaviours. Utilising the shape memory alloy (SMA) substrate, the continuously mediated strain was transferred from the substrate to Fe films through a thermally controlled shape memory effect. The pure strain modulated electronic structure in the Fe thin films was studied using in situ XPS and first-principle calculations. The result demonstrates that the compressive strain increases the overlap of outer orbits and enhances the shielding effect to core electrons, resulting in significant tunability on the binding energy of core electrons and related magnetic anisotropy.
Supervisor: Evans, David ; Zhou, Zhongfu Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.752838  DOI: Not available
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