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Title: Characterisation of CVD diamond for electronic device applications
Author: Walters, A. W.
Awarding Body: University of Wales Swansea
Current Institution: Swansea University
Date of Award: 2000
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The unique combination of physical properties displayed by the arrangement of carbon atoms recognised as diamond has fascinated scientists for hundreds of years. The electronic properties in particular are significantly superior to conventional semiconducting materials in most instances. Sadly, the currently limited supply of device quality single crystal material makes commercial production of diamond based electronic components unviable at present. Nevertheless, recent advances in the production of synthetic diamond via chemical vapour deposition (CVD) have stimulated great interest in this as a source of electronic grade material. However, in optimising the material for device applications detailed information is often required concerning the properties of the localised defect states located within the energy gap. Although there is currently significant data concerning the mid-gap states, little has been published with respect to the shallower centres that are often responsible for limiting carrier drift mobility and associated electronic properties. This study presents the first detailed exploration of the presence and influence of such shallow states form the analysis of transient photoconductivity (TPC) measurements. It is demonstrated that such procedures provide a powerful method for the study of the localised states in CVD diamond and related materials. In particular, measurements show that even in very good quality CVD diamond films, an energetically broad but structured collection of localised states exists. The energy distributions of these localised states have been calculated by employing techniques developed, refined and proven in prior studies of disordered semiconductors. During the course of the TPC studies it was observed that specimens exposed to an applied field can accumulate a significant space-charge related residual field. Clearly, this could have a considerable impact to the operation of many potential devices. Consequently, a new variant of the TPC system was developed to allow the decay of this field to be monitored as a function of time following the removal of the applied voltage.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available