{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/23697"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/23697","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Generation and relaxation of nanometer-scale roughness on the germanium(001) surface","abstract":"The surface morphology of Ge(001) during etching by low energy ions is characterized using scanning tunneling microscopy. The surfaces are bombarded by 240 eV xenon ions at various temperatures and exposure times. A well defined in-plane length scale is observed on the crystalline surfaces etched at $165270\\sp\\circ$C exhibit a regular pattern of pits. The isotropy of this pattern formation of pits argues against surface curvature dependent sputtering rate and suggests that asymmetric kinetics for the attachment of dimer vacancies at ascending and descending steps drive roughening during etching.","abstract_html":"The surface morphology of Ge(001) during etching by low energy ions is characterized using scanning tunneling microscopy. The surfaces are bombarded by 240 eV xenon ions at various temperatures and exposure times. A well defined in-plane length scale is observed on the crystalline surfaces etched at $165270\\sp\\circ$C exhibit a regular pattern of pits. The isotropy of this pattern formation of pits argues against surface curvature dependent sputtering rate and suggests that asymmetric kinetics for the attachment of dimer vacancies at ascending and descending steps drive roughening during etching.","abstract_has_math":true,"creators":["Chey, S. Jay"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics, Condensed Matter","degree_department":null,"school":null,"contributors":["Cahill, David G."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T14:23:43Z","date_published":"2011-05-07T14:23:43Z","updated_at":"2026-07-22T22:25:22Z","subjects":["Physics, Condensed Matter","Engineering, Materials Science"],"languages":["eng"],"rights":["Copyright 1996 Chey, S. Jay"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["9780591197709","AAI9712229","(UMI)AAI9712229"],"render_values":[{"text":"9780591197709","href":null,"code":true},{"text":"AAI9712229","href":null,"code":true},{"text":"(UMI)AAI9712229","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/23697","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Cahill, David G."]},{"key":"dc:creator","label":"Author","values":["Chey, S. 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Jay"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["9780591197709","AAI9712229","(UMI)AAI9712229","http://hdl.handle.net/2142/23697"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The surface morphology of Ge(001) during etching by low energy ions is characterized using scanning tunneling microscopy. The surfaces are bombarded by 240 eV xenon ions at various temperatures and exposure times. A well defined in-plane length scale is observed on the crystalline surfaces etched at $165270\\sp\\circ$C exhibit a regular pattern of pits. The isotropy of this pattern formation of pits argues against surface curvature dependent sputtering rate and suggests that asymmetric kinetics for the attachment of dimer vacancies at ascending and descending steps drive roughening during etching.","The surface defects created on Ge(001) exposed to low energy ions are characterized by scanning tunneling microscopy. The temperature during ion bombardment is 165$\\sp\\circ$C and ion energies range from 20 to 240 eV. The ion collisions create defects (vacancies and adatoms) which nucleate and form vacancy and adatom islands. The vacancy island density increases with increasing ion energy. The increased rate for vacancies is attributed to clustering of defects. The sputtering yield for 20 eV ion is approximately 10$\\sp{-3}$ but the net yield for surface defects (sum of adatoms and vacancies) is an order of magnitude higher, $\\sim$10$\\sp{-2}$, due to adatom-vacancy pair creation.","Relaxation of a nanometer length scale roughness of Ge(001) is studied by scanning tunneling microscopy. Rough surfaces with in-plane length scale L of $37\\sim 118$ nm are created by ion etching and annealed at $245<T<325\\sp\\circ$C. The activation energy of 1.9 $\\pm$ 0.25 eV for surface relaxation is observed. The surface height profile decays as $\\sim (1+t/\\tau )\\sp{-1/2}$ where t is annealing time and $\\tau$ is the relaxation time constant. A scaling law of $\\tau = L\\sp{2.2\\pm 0.4}$ is observed. This is inconsistent with the continuum model which predicts an exponential decay of the height profile and a scaling exponent of 4. The result is consistent with the non-conserved, step mobility limited model by Uwaha.","Made available in DSpace on 2011-05-07T14:23:43Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9712229.pdf: 4615546 bytes, checksum: 1c11fc598d7641b5b6c2b83966f91b3d (MD5) Previous issue date: 1996","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:06:14Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:31:47-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["Generation and relaxation of nanometer-scale roughness on the germanium(001) surface"]}]}],"canonical_facts":{"dc:contributor":["Cahill, David G."],"dc:creator":["Chey, S. Jay"],"dc:date":["2011-05-07T14:23:43Z","10000-01-01","1996"],"dc:description":["The surface morphology of Ge(001) during etching by low energy ions is characterized using scanning tunneling microscopy. The surfaces are bombarded by 240 eV xenon ions at various temperatures and exposure times. A well defined in-plane length scale is observed on the crystalline surfaces etched at $165270\\sp\\circ$C exhibit a regular pattern of pits. The isotropy of this pattern formation of pits argues against surface curvature dependent sputtering rate and suggests that asymmetric kinetics for the attachment of dimer vacancies at ascending and descending steps drive roughening during etching.","The surface defects created on Ge(001) exposed to low energy ions are characterized by scanning tunneling microscopy. The temperature during ion bombardment is 165$\\sp\\circ$C and ion energies range from 20 to 240 eV. The ion collisions create defects (vacancies and adatoms) which nucleate and form vacancy and adatom islands. The vacancy island density increases with increasing ion energy. The increased rate for vacancies is attributed to clustering of defects. The sputtering yield for 20 eV ion is approximately 10$\\sp{-3}$ but the net yield for surface defects (sum of adatoms and vacancies) is an order of magnitude higher, $\\sim$10$\\sp{-2}$, due to adatom-vacancy pair creation.","Relaxation of a nanometer length scale roughness of Ge(001) is studied by scanning tunneling microscopy. Rough surfaces with in-plane length scale L of $37\\sim 118$ nm are created by ion etching and annealed at $245<T<325\\sp\\circ$C. The activation energy of 1.9 $\\pm$ 0.25 eV for surface relaxation is observed. The surface height profile decays as $\\sim (1+t/\\tau )\\sp{-1/2}$ where t is annealing time and $\\tau$ is the relaxation time constant. A scaling law of $\\tau = L\\sp{2.2\\pm 0.4}$ is observed. This is inconsistent with the continuum model which predicts an exponential decay of the height profile and a scaling exponent of 4. The result is consistent with the non-conserved, step mobility limited model by Uwaha.","Made available in DSpace on 2011-05-07T14:23:43Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9712229.pdf: 4615546 bytes, checksum: 1c11fc598d7641b5b6c2b83966f91b3d (MD5) Previous issue date: 1996","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:06:14Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:31:47-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"],"dc:identifier":["9780591197709","AAI9712229","(UMI)AAI9712229","http://hdl.handle.net/2142/23697"],"dc:language":["eng"],"dc:rights":["Copyright 1996 Chey, S. Jay"],"dc:subject":["Physics, Condensed Matter","Engineering, Materials Science"],"dc:title":["Generation and relaxation of nanometer-scale roughness on the germanium(001) surface"],"dc:type":["text"],"thesis:degree_discipline":["Physics, Condensed Matter","Engineering, Materials Science"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:22Z"}