M'SONE MSc Abstract - 2011

Supervisor : Dr Dazmen Mavunda : NECSA / UJ

PROJECT TITLE: A study of the interaction of Charge Carriers and Defects in Diamond

It is well known that the presence of defects in diamond, including CVD specimens, not only dictates but also affects the response of diamond to radiation in different ways. Mavunda et. al 2008 have shown that electron spin resonance (ESR), thermo-luminescence (TL), Raman spectroscopy and ultraviolet (UV) spectroscopy can be used as a tool to characterize CVD diamond in respect of electronic applications[1].

This projects extends this work by directly correlating various diamond characterization techniques in high resolution imaging mode, and correlating these with a map of the diamond electronic response as obtained by Ion Beam Induced Current (IBIC) measurements.

The project therefore involves the quantitative mapping of certain defect distributions in high (device) quality CVD and HPHT synthetic diamond. Many of these characterization techniques can be performed in imaging mode at a synchrotron. For example, XRF, IR-, UV- and Vis-spectroscopy and also X-ray Topography (White Beam, Monochromatic Plane Wave and Rocking curve imaging). Work will then proceed to correlate defects with maps of ion beam induced current measurements (performed at iThemba LABS (Gauteng)) so as to learn the modification of charge carrier transport properties by various defects in a selection of diamonds configured as planar detectors.

Techniques for imaging will include :

  1. Synchrotron Maps (XRF) elemental analysis of impurities
  2. IR map nitrogen aggregates
  3. UV-Vis map Vacc, boron, nitrogen
  4. X-ray topography (Stacking faults, dislocations, strain fields from inhomogenous impurity distributions and inclusions).