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dc.contributor.advisor Evans, Andrew Roberts, Owain Rhys 2010-04-30T08:03:03Z 2010-04-30T08:03:03Z 2009-09
dc.identifier.citation Roberts, O. R. (2009) The Application of Real-Time Photoelectron Spectroscopy to Carbon-Based Semiconductors. PhD Thesis, Institute of maths and Physics, Aberystwyth University en
dc.description.abstract This thesis reports on the development of a new method for studying the growth of thin films and the dynamics of surface processes. Real-time photoelectron spectroscopy enabled by advances in electron detection technology has been applied to the study of metal overlayers on a p-type CVD (001) diamond single crystal and tin (II) phthalocyanine (SnPc) overlayers on Si (111), GaAs (001) and polycrystalline Au substrates. The performance of the Aberystwyth real-time electron spectroscopy (REES) system is also reviewed. Temperature-dependent real-time photoelectron studies of an oxygen-terminated boron-doped CVD (001) single crystal diamond is performed with a fully reversible temperature dependent Fermi level shift of ~ 1 eV observed on the oxygen-terminated 1 x 1 surface up to a temperature of 700 °C. This shift is found to correlate with oxygen coverage where the maximum reversible shift reduces in magnitude with decreasing oxygen coverage. The growth of aluminium contacts on the (001) diamond surface is investigated with the formation of a Schottky contact for which current-voltage measurements yield a barrier height of 1.05 eV and an ideality factor of 1.4. Real-time measurements monitor the formation of the contact revealing the transition from layered to clustered growth of the aluminium film during in vacuo deposition. During annealing of the contact to 860 °C real-time measurements reveal a direct correlation between the transition from Schottky to Ohmic behaviour and the formation of interfacial carbide at 482 °C. Deposition of iron on the (001) diamond surface is found to form an uniform layer with iron carbide species present at the interface. Subsequent annealing of the diamond to 850 °C results in the formation of a graphite layer with iron acting as a catalyst for the graphitisation process. AFM and NEXAFS of the resulting graphite layer reveal an ordered surface. A mechanism is proposed for the graphitisation. Finally, the growth of SnPc is investigated on Si (111), GaAs (001) and polycrystalline Au. Growth is found to proceed in two stages and re-organisation of the molecules is detected by real-time measurements and found to continue after deposition for a period of up to 30 minutes. Studies also suggest that substrate temperature affects the angle of stacking and the rate of molecular re-organisation. A theoretical molecular model for this re-organisation was successfully developed. en
dc.description.sponsorship EPSRC; Aberystwyth University Garrod Thomas Scholarship Fund; Element Six Ltd, Ascot, UK en
dc.language.iso en en
dc.publisher Aberystwyth University en
dc.title The Application of Real-Time Photoelectron Spectroscopy to Carbon-Based Semiconductors en
dc.type Text en
dc.type.publicationtype doctoral thesis en

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