In recent years advances in the processing and purification of detonation nanodiamonds has renewed interest into their research, from the basic properties of detonation nanodiamonds to their applications in areas from electronics to biology. Using a colloid of mono dispersed detonation nanodiamonds it is possible to coat various substrate materials. This thesis reports on the suitability and enhancement of nanodiamond coatings for electronic applications. Atomic force microscopy is used to investigate the deposition of nanodiamond particles on substrates. The electrical characteristics of mono-dispersed nanodiamond layers are investigated using impedance spectroscopy, establishing that the layers have high quality dielectric characteristics. Hydrogen terminated CVD diamond is known to have a negative electron affinity (NEA), making it a suitable material for secondary electron emission. This thesis investigates using and optimising nanodiamond coatings on microchannel plates (MCPs) to increase the secondary electron yield of these devices, thereby improving the performance of image intensifiers. The as-received nanodiamond is covered with surface functional groups dependent on post detonation treatments for cleaning and deaggregation. Treatments have been designed which modify the surface groups for homogeneity, followed by an oxidation treatment to provide a platform for metallisation, notably caesium oxide which is known to give a stable and larger NEA surface thus further improving the secondary electron yield. Fourier transform infra-red spectroscopy and has been used to investigate the presence of functional groups. A comprehensive study of the secondary electron emission yield of nanodiamond coatings after various surface treatments is presented. The most effective treatment is found to be a low temperature chemical vapour deposition process which is compatible with the fragile MCP structure. SEM and Raman spectroscopy have been used to provide an insight into the changes of the material, which remains nanodiamond-like. These are the first such results from nanodiamond material.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:625860 |
| Date | January 2012 |
| Creators | Chaudhary, A. N. |
| Publisher | University College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://discovery.ucl.ac.uk/1349961/ |
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