{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/90957"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/90957","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"First principles calculations on ZnO non-equilibrium phase","abstract":"In this thesis work, the electronic and optical properties for the non-equilibrium boron-nitride phase of ZnO have been studied. To understand the difference between the BN phase and the equilibrium WZ phase, first principles approaches such as DFT, hybrid functional and the GW approximation have been studied and applied. The lattice constant has been obtained by performing full relaxation within the DFT approximation. With the DFT optimized structure, we calculated the band structures and band gaps for both phases. We have found an about 0.2 eV larger band gap for BN phase with all methods. A discrepancy between the lattice constant obtained from experiment and that from simulation has also been investigated. We calculated the band structure for both the experimental lattice and the computed lattice obtained from relaxation. We have found an inconsistency between the experimental lattice constant and the experimental band gap. Further, by solving the Bethe-Salpeter Equation, excitonic effect has been included and the exact optical spectrum for both structure has been obtained. We have found a large optical anisotropy for BN structure. Lastly we calculated the exciton binding energy for the BN phase and have found a larger excitonic effect in this phase.","abstract_html":"In this thesis work, the electronic and optical properties for the non-equilibrium boron-nitride phase of ZnO have been studied. To understand the difference between the BN phase and the equilibrium WZ phase, first principles approaches such as DFT, hybrid functional and the GW approximation have been studied and applied. The lattice constant has been obtained by performing full relaxation within the DFT approximation. With the DFT optimized structure, we calculated the band structures and band gaps for both phases. We have found an about 0.2 eV larger band gap for BN phase with all methods. A discrepancy between the lattice constant obtained from experiment and that from simulation has also been investigated. We calculated the band structure for both the experimental lattice and the computed lattice obtained from relaxation. We have found an inconsistency between the experimental lattice constant and the experimental band gap. Further, by solving the Bethe-Salpeter Equation, excitonic effect has been included and the exact optical spectrum for both structure has been obtained. We have found a large optical anisotropy for BN structure. Lastly we calculated the exciton binding energy for the BN phase and have found a larger excitonic effect in this phase.","abstract_has_math":false,"creators":["Zhang, Xiao"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Mechanical Engineering","degree_department":null,"school":null,"contributors":["Ertekin, Elif","Schleife, André"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2016,"date_issued":"2016-07-07T21:18:03Z","date_published":"2016-07-07T21:18:03Z","updated_at":"2026-07-22T22:26:34Z","subjects":["Zinc Oxide","Electronic structure","Optical Absorption","GW approximation","Bethe-Salpeter Equation"],"languages":["en"],"rights":["Copyright 2016 Xiao Zhang"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/90957","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Ertekin, Elif","Schleife, André"]},{"key":"dc:creator","label":"Author","values":["Zhang, Xiao"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2016-07-07T21:18:03Z","2018-07-08T09:15:30Z","2016-04-27","2016-05"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Zinc Oxide","Electronic structure","Optical Absorption","GW approximation","Bethe-Salpeter Equation"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2016 Xiao Zhang"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/90957"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["In this thesis work, the electronic and optical properties for the non-equilibrium boron-nitride phase of ZnO have been studied. To understand the difference between the BN phase and the equilibrium WZ phase, first principles approaches such as DFT, hybrid functional and the GW approximation have been studied and applied. The lattice constant has been obtained by performing full relaxation within the DFT approximation. With the DFT optimized structure, we calculated the band structures and band gaps for both phases. We have found an about 0.2 eV larger band gap for BN phase with all methods. A discrepancy between the lattice constant obtained from experiment and that from simulation has also been investigated. We calculated the band structure for both the experimental lattice and the computed lattice obtained from relaxation. We have found an inconsistency between the experimental lattice constant and the experimental band gap. Further, by solving the Bethe-Salpeter Equation, excitonic effect has been included and the exact optical spectrum for both structure has been obtained. We have found a large optical anisotropy for BN structure. Lastly we calculated the exciton binding energy for the BN phase and have found a larger excitonic effect in this phase.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2018-05-01","The student, Xiao Zhang, accepted the attached license on 2016-04-25 at 14:38.","The student, Xiao Zhang, submitted this Thesis for approval on 2016-04-25 at 14:39.","This Thesis was approved for publication on 2016-04-27 at 09:20.","DSpace SAF Submission Ingestion Package generated from Vireo submission #9479 on 2016-07-07 at 14:18:00","Made available in DSpace on 2016-07-07T21:18:03Z (GMT). No. of bitstreams: 2 ZHANG-THESIS-2016.pdf: 1124792 bytes, checksum: 58195ff1acac9435c0fd1c35fc19393f (MD5) LICENSE.txt: 4207 bytes, checksum: dad3829871db6a1c02b7bd4552478b08 (MD5) Previous issue date: 2016-04-27","Embargo set by: Seth Robbins for item 93312 Lift date: 2018-07-07T21:18:16Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Limited Restriction Lifted for Item 93312 on 2018-07-08T09:15:30Z."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["First principles calculations on ZnO non-equilibrium phase"]}]}],"canonical_facts":{"dc:contributor":["Ertekin, Elif","Schleife, André"],"dc:creator":["Zhang, Xiao"],"dc:date":["2016-07-07T21:18:03Z","2018-07-08T09:15:30Z","2016-04-27","2016-05"],"dc:description":["In this thesis work, the electronic and optical properties for the non-equilibrium boron-nitride phase of ZnO have been studied. To understand the difference between the BN phase and the equilibrium WZ phase, first principles approaches such as DFT, hybrid functional and the GW approximation have been studied and applied. The lattice constant has been obtained by performing full relaxation within the DFT approximation. With the DFT optimized structure, we calculated the band structures and band gaps for both phases. We have found an about 0.2 eV larger band gap for BN phase with all methods. A discrepancy between the lattice constant obtained from experiment and that from simulation has also been investigated. We calculated the band structure for both the experimental lattice and the computed lattice obtained from relaxation. We have found an inconsistency between the experimental lattice constant and the experimental band gap. Further, by solving the Bethe-Salpeter Equation, excitonic effect has been included and the exact optical spectrum for both structure has been obtained. We have found a large optical anisotropy for BN structure. Lastly we calculated the exciton binding energy for the BN phase and have found a larger excitonic effect in this phase.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2018-05-01","The student, Xiao Zhang, accepted the attached license on 2016-04-25 at 14:38.","The student, Xiao Zhang, submitted this Thesis for approval on 2016-04-25 at 14:39.","This Thesis was approved for publication on 2016-04-27 at 09:20.","DSpace SAF Submission Ingestion Package generated from Vireo submission #9479 on 2016-07-07 at 14:18:00","Made available in DSpace on 2016-07-07T21:18:03Z (GMT). No. of bitstreams: 2 ZHANG-THESIS-2016.pdf: 1124792 bytes, checksum: 58195ff1acac9435c0fd1c35fc19393f (MD5) LICENSE.txt: 4207 bytes, checksum: dad3829871db6a1c02b7bd4552478b08 (MD5) Previous issue date: 2016-04-27","Embargo set by: Seth Robbins for item 93312 Lift date: 2018-07-07T21:18:16Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Limited Restriction Lifted for Item 93312 on 2018-07-08T09:15:30Z."],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/90957"],"dc:language":["en"],"dc:rights":["Copyright 2016 Xiao Zhang"],"dc:subject":["Zinc Oxide","Electronic structure","Optical Absorption","GW approximation","Bethe-Salpeter Equation"],"dc:title":["First principles calculations on ZnO non-equilibrium phase"],"dc:type":["text"],"thesis:degree_discipline":["Mechanical Engineering"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:34Z"}