An investigation into the effect of oxygen on the three ultraviolet optical absorption bands in magnesium oxide was carried out. These peaks were located at 5.75, 5.0 and 4.40 eV within the range 212 to 350 mu.
The single crystal platelets were heated in air or oxygen for increasing times at various temperatures. It was found that the increase in peak height with time followed a diffusion relation.
A mechanism of formation of the centers causing the 5.75 and 4.40 eV peaks was proposed. The mechanism was based on the oxidation of iron and manganese impurities and the diffusion of magnesium to the crystal surface. The absorbing center was defined as (Fe⁺³∙VMg⁺²). From this it was shown that the diffusion process governing both the 5.75 and the 4.40 eV peaks followed the same Arrhenius relation: D=1.7 X 10⁵ e -77,000/RT cm²/sec. over the temperature range of 800 to 1100° C.
No similar conclusions could be drawn concerning the 5.0 eV peak. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/39335 |
| Date | January 1961 |
| Creators | Evans, Dewi Gordon Sutcliffe |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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