Barbu, Bianca (2009) Electrical and electrochemical characterisation of single crystal diamond. PhD thesis, University of Warwick.

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Abstract

The overall aim of this thesis is to examine the electrical and electrochemical
properties of single crystal intrinsic and boron doped diamond grown by
chemical vapour deposition.
Techniques such as AFM, C-AFM, FE-SEM, PL imaging, in air and in solution
Hall and resistivity measurements, FET, cyclic voltammetry and SECM have
been employed.
The results from studying single crystal intrinsic H-terminated diamond with
different surface preparations are reported. In air and in solution measurements
suggest a similar behaviour for polished surfaces. Different mechanisms (for in
air or in solution experiments) have to be applied in order to interpret the
electrical transport data correctly. Electrochemistry of H-terminated single
crystal diamond with well defined redox couples has been proven, but the
electron transfer rates are relatively slow. Initial SECM experiments indicate that
the surface is homogeneously active, but can be easily damaged.
Single crystal boron doped diamonds with moderate (< 1020 cm-3 boron) doping
levels have been examined. PL imaging and C-AFM highlighted regions with
different doping level and different conductivity even though the material is
single crystal. In air electrical measurements demonstrated that the bulk mobility
and carrier concentration are independent of the surface termination (O- or H-).
No redox activity (or very little) was observed when the samples were O-terminated;
quasi-reversible behaviour and sluggish electron transfer kinetics was
observed for H-terminated surfaces.
The properties of a as-grown single crystal boron doped diamond with high (>
1020 cm-3 boron) doping levels have also been investigated. Electrical studies
confirmed that the diamond behaved like a metallic conductor. Large background
currents were observed when CVs were used to study the O-terminated sample in
FcTMA+, but the origin of this signal are not clear. For both Ru(NH3)6
3+ and
FcTMA+ the metallic boron doped single crystal diamond electrode showed
quasi-reversible behaviour. The peak to peak separation is smaller for the H-termination
than for the O-termination. Preliminary SECM studies showed that
the electrode’s surface was homogeneously active.

Item Type:	Thesis (PhD)
Subjects:	Q Science > QC Physics T Technology > TK Electrical engineering. Electronics Nuclear engineering
Library of Congress Subject Headings (LCSH):	Diamonds -- Electric properties, Diamonds -- Analysis, Boron
Official Date:	December 2009
Dates:	Date Event December 2009 Submitted
Institution:	University of Warwick
Theses Department:	Department of Physics
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Newton, M. E. (Mark E.) ; Macpherson, Julie V.
Extent:	xxv, 221 p. : ill., charts
Language:	eng

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