{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/35205"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/35205","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Fluctuation Electron Microscopy of Medium-Range Order in Amorphous Silicon","abstract":"Fluctuation electron microscopy is a transmission electron microscopy technique for studying medium-range order in disordered materials. We compute the variance for the image intensity of low-resolution hollow-cone dark field electron micrographs as a function of the diffracting condition and microscope resolution. The variance is sensitive to fluctuations in diffraction from mesoscopic volumes of the sample. It carries information about medium-range order via the three- and four-body atomic distribution functions. Fluctuation microscopy has been applied to the study of amorphous silicon, with and without alloying with hydrogen. We find that amorphous silicon has significant medium-range order, more than can be described by the conventional continuous random network model. The structure is better described by a paracrystalline model, which consists of strained topologically crystalline grains which may or may not be embedded in a more disordered matrix. Experiments show a continuous evolution of medium-range order in films deposited with increasing substrate temperature from the amorphous to polycrystalline regimes, which is counter to the belief that this structural transition is a discontinuous order-disorder phase transition. In the paracrystalline model, this increase is caused by the topologically crystalline grains growing, or occupying a greater volume fraction, or both. Experiments also show that hydrogenated amorphous silicon deposited by a variety of methods shares the paracrystalline structure. The medium-range order of hydrogenated amorphous silicon is affected by exposure to visible-spectrum white light. Films deposited by different methods have different responses, which may be connected to differences in the creation of metastable electrical defects known as the Staebler-Wronski effect.","abstract_html":"Fluctuation electron microscopy is a transmission electron microscopy technique for studying medium-range order in disordered materials. We compute the variance for the image intensity of low-resolution hollow-cone dark field electron micrographs as a function of the diffracting condition and microscope resolution. The variance is sensitive to fluctuations in diffraction from mesoscopic volumes of the sample. It carries information about medium-range order via the three- and four-body atomic distribution functions. Fluctuation microscopy has been applied to the study of amorphous silicon, with and without alloying with hydrogen. We find that amorphous silicon has significant medium-range order, more than can be described by the conventional continuous random network model. The structure is better described by a paracrystalline model, which consists of strained topologically crystalline grains which may or may not be embedded in a more disordered matrix. Experiments show a continuous evolution of medium-range order in films deposited with increasing substrate temperature from the amorphous to polycrystalline regimes, which is counter to the belief that this structural transition is a discontinuous order-disorder phase transition. In the paracrystalline model, this increase is caused by the topologically crystalline grains growing, or occupying a greater volume fraction, or both. Experiments also show that hydrogenated amorphous silicon deposited by a variety of methods shares the paracrystalline structure. The medium-range order of hydrogenated amorphous silicon is affected by exposure to visible-spectrum white light. Films deposited by different methods have different responses, which may be connected to differences in the creation of metastable electrical defects known as the Staebler-Wronski effect.","abstract_has_math":false,"creators":["Voyles, Paul Marriner"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2012,"date_issued":"2012-11-11T17:25:08Z","date_published":"2012-11-11T17:25:08Z","updated_at":"2026-07-22T22:25:31Z","subjects":["amorphous","silicon","microscopy","diffraction","paracrystalline","dark-field","medium-range order (mro)","coherence","semiconductors","hydrogenated","applescripts"],"languages":["en"],"rights":["Voyles 2001 ©"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/35205","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Voyles, Paul Marriner"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2012-11-11T17:25:08Z","10000-01-01","2001"]},{"key":"dc:type","label":"Dc Type","values":["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","microscopy","diffraction","paracrystalline","dark-field","medium-range order (mro)","coherence","semiconductors","hydrogenated","applescripts"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Voyles 2001 ©"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/35205"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Fluctuation electron microscopy is a transmission electron microscopy technique for studying medium-range order in disordered materials. We compute the variance for the image intensity of low-resolution hollow-cone dark field electron micrographs as a function of the diffracting condition and microscope resolution. The variance is sensitive to fluctuations in diffraction from mesoscopic volumes of the sample. It carries information about medium-range order via the three- and four-body atomic distribution functions. Fluctuation microscopy has been applied to the study of amorphous silicon, with and without alloying with hydrogen. We find that amorphous silicon has significant medium-range order, more than can be described by the conventional continuous random network model. The structure is better described by a paracrystalline model, which consists of strained topologically crystalline grains which may or may not be embedded in a more disordered matrix. Experiments show a continuous evolution of medium-range order in films deposited with increasing substrate temperature from the amorphous to polycrystalline regimes, which is counter to the belief that this structural transition is a discontinuous order-disorder phase transition. In the paracrystalline model, this increase is caused by the topologically crystalline grains growing, or occupying a greater volume fraction, or both. Experiments also show that hydrogenated amorphous silicon deposited by a variety of methods shares the paracrystalline structure. The medium-range order of hydrogenated amorphous silicon is affected by exposure to visible-spectrum white light. Films deposited by different methods have different responses, which may be connected to differences in the creation of metastable electrical defects known as the Staebler-Wronski effect.","Submitted by Elias Lopez (erlopez2@illinois.edu) on 2012-11-11T17:25:08Z No. of bitstreams: 1 Voyles_Paul_Marriner.pdf: 5345923 bytes, checksum: 897c84f9715da8a6e0223866654e495a (MD5)","Made available in DSpace on 2012-11-11T17:25:08Z (GMT). No. of bitstreams: 1 Voyles_Paul_Marriner.pdf: 5345923 bytes, checksum: 897c84f9715da8a6e0223866654e495a (MD5) Previous issue date: 2001","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Elias Lopez (erlopez2@illinois.edu) on 2012-11-14T02:27:19Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:35:26-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Publisher has not yet granted open access permission","Publisher has not yet granted open access permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["Fluctuation Electron Microscopy of Medium-Range Order in Amorphous Silicon"]}]}],"canonical_facts":{"dc:creator":["Voyles, Paul Marriner"],"dc:date":["2012-11-11T17:25:08Z","10000-01-01","2001"],"dc:description":["Fluctuation electron microscopy is a transmission electron microscopy technique for studying medium-range order in disordered materials. We compute the variance for the image intensity of low-resolution hollow-cone dark field electron micrographs as a function of the diffracting condition and microscope resolution. The variance is sensitive to fluctuations in diffraction from mesoscopic volumes of the sample. It carries information about medium-range order via the three- and four-body atomic distribution functions. Fluctuation microscopy has been applied to the study of amorphous silicon, with and without alloying with hydrogen. We find that amorphous silicon has significant medium-range order, more than can be described by the conventional continuous random network model. The structure is better described by a paracrystalline model, which consists of strained topologically crystalline grains which may or may not be embedded in a more disordered matrix. Experiments show a continuous evolution of medium-range order in films deposited with increasing substrate temperature from the amorphous to polycrystalline regimes, which is counter to the belief that this structural transition is a discontinuous order-disorder phase transition. In the paracrystalline model, this increase is caused by the topologically crystalline grains growing, or occupying a greater volume fraction, or both. Experiments also show that hydrogenated amorphous silicon deposited by a variety of methods shares the paracrystalline structure. The medium-range order of hydrogenated amorphous silicon is affected by exposure to visible-spectrum white light. Films deposited by different methods have different responses, which may be connected to differences in the creation of metastable electrical defects known as the Staebler-Wronski effect.","Submitted by Elias Lopez (erlopez2@illinois.edu) on 2012-11-11T17:25:08Z No. of bitstreams: 1 Voyles_Paul_Marriner.pdf: 5345923 bytes, checksum: 897c84f9715da8a6e0223866654e495a (MD5)","Made available in DSpace on 2012-11-11T17:25:08Z (GMT). No. of bitstreams: 1 Voyles_Paul_Marriner.pdf: 5345923 bytes, checksum: 897c84f9715da8a6e0223866654e495a (MD5) Previous issue date: 2001","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Elias Lopez (erlopez2@illinois.edu) on 2012-11-14T02:27:19Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:35:26-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Publisher has not yet granted open access permission","Publisher has not yet granted open access permission","U of I Only"],"dc:identifier":["http://hdl.handle.net/2142/35205"],"dc:language":["en"],"dc:rights":["Voyles 2001 ©"],"dc:subject":["amorphous","silicon","microscopy","diffraction","paracrystalline","dark-field","medium-range order (mro)","coherence","semiconductors","hydrogenated","applescripts"],"dc:title":["Fluctuation Electron Microscopy of Medium-Range Order in Amorphous Silicon"],"dc:type":["text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-22T22:25:31Z"}