Show simple item record

dc.contributor.author Pu, Anle en_US
dc.date.accessioned 2007-06-01T19:21:35Z
dc.date.available 2007-06-01T19:21:35Z
dc.date.issued 2000-05-01T00:00:00Z en_US
dc.identifier.uri http://hdl.handle.net/1993/2337
dc.description.abstract Vacancy-type defects in the four main types of diamond (Ia, Ib, IIa and IIb) were investigated using positron lifetime, Doppler broadening and optical absorption spectroscopies. In unirradiated samples vacancy clusters were found in all types, synthetic as well as natural. These clusters are situated in highly defected regions, rather than homogeneously distributed, and their concentration varies significantly from sample to sample. For synthetic Ib diamonds vacancy clusters were investigated as a function of nitrogen content. We have developed a simplified model for the trapping of positrons by ' negatively' charged vacancies. By solving the differential equations pertaining to the population of positron states, expressions for the experimentally observable positron parameters (lifetimes, their intensities and the Doppler broadening parameter S) were obtained. (Abstract shortened by UMI.) en_US
dc.format.extent 6158822 bytes
dc.format.extent 184 bytes
dc.format.mimetype application/pdf
dc.format.mimetype text/plain
dc.language en en_US
dc.language.iso en_US
dc.title Positron annihilation investigation of vacancies in as-grown and electron irradiated dia onds en_US
dc.degree.discipline Physics & Astronomy en_US
dc.degree.level Master of Science (M.Sc.) en_US


Files in this item

This item appears in the following Collection(s)

Show simple item record

View Statistics