{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/25309"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/25309","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Microwave studies of amorphous silicon","abstract":"Electron paramagnetic resonance and electron spin relaxation rates of the intrinsic paramagnetic center (g=2.0055) in amorphous silicon have been studied in the 0.3 -1.2 K temperature range. Various sample preparation techniques were used, including ion implantation, sputtering, arid vacuum evaporation. The temperature dependence of the spin lattice relaxation rates depends somewhat on sample preparation but is always very close to simple T power laws. The n values observed in this study fall into two ranges: 2.09 -2.36 and 3.26 -3.47. Comparison of measurements at 9.3 GHz and 16.5 GHz indicates that the observed rates are independent or very nearly independent of microwave frequency and applied magnetic field. Conventional one and two phonon spin lattice relaxation mechanisms cannot account for the observed temperature dependences. A theory involving spin lattice relaxation by coupling to a distribution of two level systems (TLS) is presented. The theory is adjusted so that it can be applied in the relevant temperature range and its predictions are compared to the experimental results. An attempt is made to identify the TLS and the TLS-spin coupling using electron-nuclear double rescnance (ENDOR), microwave frequency dielectric absorption, and magn","abstract_html":"Electron paramagnetic resonance and electron spin relaxation rates of the intrinsic paramagnetic center (g=2.0055) in amorphous silicon have been studied in the 0.3 -1.2 K temperature range. Various sample preparation techniques were used, including ion implantation, sputtering, arid vacuum evaporation. The temperature dependence of the spin lattice relaxation rates depends somewhat on sample preparation but is always very close to simple T power laws. The n values observed in this study fall into two ranges: 2.09 -2.36 and 3.26 -3.47. Comparison of measurements at 9.3 GHz and 16.5 GHz indicates that the observed rates are independent or very nearly independent of microwave frequency and applied magnetic field. Conventional one and two phonon spin lattice relaxation mechanisms cannot account for the observed temperature dependences. A theory involving spin lattice relaxation by coupling to a distribution of two level systems (TLS) is presented. The theory is adjusted so that it can be applied in the relevant temperature range and its predictions are compared to the experimental results. An attempt is made to identify the TLS and the TLS-spin coupling using electron-nuclear double rescnance (ENDOR), microwave frequency dielectric absorption, and magn","abstract_has_math":false,"creators":["Askew, Thomas Rendall"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Stapleton, H.J."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-06-07T14:10:40Z","date_published":"2011-06-07T14:10:40Z","updated_at":"2026-07-22T22:25:24Z","subjects":["amorphous silicon","electron paramagnetic resonance","electron spin relaxation"],"languages":["en"],"rights":["1984 Thomas Rendall Askew"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["826531"],"render_values":[{"text":"826531","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/25309","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Stapleton, H.J."]},{"key":"dc:creator","label":"Author","values":["Askew, Thomas Rendall"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-06-07T14:10:40Z","10000-01-01","1984"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation / Thesis","text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["amorphous silicon","electron paramagnetic resonance","electron spin relaxation"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["1984 Thomas Rendall Askew"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["826531","http://hdl.handle.net/2142/25309"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Electron paramagnetic resonance and electron spin relaxation rates of the intrinsic paramagnetic center (g=2.0055) in amorphous silicon have been studied in the 0.3 -1.2 K temperature range. Various sample preparation techniques were used, including ion implantation, sputtering, arid vacuum evaporation. The temperature dependence of the spin lattice relaxation rates depends somewhat on sample preparation but is always very close to simple T power laws. The n values observed in this study fall into two ranges: 2.09 -2.36 and 3.26 -3.47. Comparison of measurements at 9.3 GHz and 16.5 GHz indicates that the observed rates are independent or very nearly independent of microwave frequency and applied magnetic field. Conventional one and two phonon spin lattice relaxation mechanisms cannot account for the observed temperature dependences. A theory involving spin lattice relaxation by coupling to a distribution of two level systems (TLS) is presented. The theory is adjusted so that it can be applied in the relevant temperature range and its predictions are compared to the experimental results. An attempt is made to identify the TLS and the TLS-spin coupling using electron-nuclear double rescnance (ENDOR), microwave frequency dielectric absorption, and magn","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-07T14:10:40Z No. of bitstreams: 1 1984_askew.pdf: 4877314 bytes, checksum: e1c4b813ceef1b7595ef79be0628d1ed (MD5)","Made available in DSpace on 2011-06-07T14:10:40Z (GMT). No. of bitstreams: 1 1984_askew.pdf: 4877314 bytes, checksum: e1c4b813ceef1b7595ef79be0628d1ed (MD5) Previous issue date: 1984","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-06-07T14:10:40Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:09:01-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"]},{"key":"dc:title","label":"Title","values":["Microwave studies of amorphous silicon"]}]}],"canonical_facts":{"dc:contributor":["Stapleton, H.J."],"dc:creator":["Askew, Thomas Rendall"],"dc:date":["2011-06-07T14:10:40Z","10000-01-01","1984"],"dc:description":["Electron paramagnetic resonance and electron spin relaxation rates of the intrinsic paramagnetic center (g=2.0055) in amorphous silicon have been studied in the 0.3 -1.2 K temperature range. Various sample preparation techniques were used, including ion implantation, sputtering, arid vacuum evaporation. The temperature dependence of the spin lattice relaxation rates depends somewhat on sample preparation but is always very close to simple T power laws. The n values observed in this study fall into two ranges: 2.09 -2.36 and 3.26 -3.47. Comparison of measurements at 9.3 GHz and 16.5 GHz indicates that the observed rates are independent or very nearly independent of microwave frequency and applied magnetic field. Conventional one and two phonon spin lattice relaxation mechanisms cannot account for the observed temperature dependences. A theory involving spin lattice relaxation by coupling to a distribution of two level systems (TLS) is presented. The theory is adjusted so that it can be applied in the relevant temperature range and its predictions are compared to the experimental results. An attempt is made to identify the TLS and the TLS-spin coupling using electron-nuclear double rescnance (ENDOR), microwave frequency dielectric absorption, and magn","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-07T14:10:40Z No. of bitstreams: 1 1984_askew.pdf: 4877314 bytes, checksum: e1c4b813ceef1b7595ef79be0628d1ed (MD5)","Made available in DSpace on 2011-06-07T14:10:40Z (GMT). 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