{"id":{"repo_id":"njit","oai_identifier":"oai:digitalcommons.njit.edu:dissertations-1951"},"canonical_url":"https://search.dev.ndltd.org/etd/njit/oai:digitalcommons.njit.edu:dissertations-1951","repository":{"repo_id":"njit","name":"NJIT","base_url":"https://digitalcommons.njit.edu/do/oai/"},"display":{"title":"Synchrotron radiation-based characterization of GaN- based MQW structures and strongly correlated materials","abstract":"The following dissertation applies synchrotron radiation-based characterization techniques to the fields of gallium nitrides, multiferroic manganites, and self-assembled nano-domain oxide films. These material systems were chosen due to their unusual properties and potential device applications, which have made them very attractive to the scientific community. Synchrotron-based High Resolution X-ray Diffraction (HRXRD) was used to characterize the structural properties of GaN-based multiple quantum well (MQW) structures grown on trapezoidal shaped GaN ridges. Results where interpreted within the framework of vapor-phase diffusion and surface-migration effects during the metalorganic vapor phase epitaxial growth. The relatively short diffusion length of group- III precursors and growth enhancement, due to facet migration was found to have significant effects on the MQW formation. The use of synchrotron based HRXRD and in particular cross-sectional reciprocal space mapping (RSM) was then extended to studying the intriguing structural properties of a ZnMnGaO_4 film epitaxially grown on MgO (001) substrate. The results of this study helped in identifying the ZnMnGaO_4 film, as consisting of a self-assembled nano- checkerboard structure of highly aligned and regularly spaced vertical nanorods. The results demonstrated the importance of lattice distortion symmetry at the phase boundaries as a means for the coherent coexistence of two domain types within the film volume. Synchrotron-based far-infrared spectroscopy was performed at low temperatures on the single crystal multiferroic manganite HoMn_2O_5. A number of the infrared-active excitations were attributed to electric-dipole transitions between ligand-field split states of Ho^{3+} ions. It is proposed that the proximity in energy between magnons and Ho^{3+} ligand fields (LF) might connect the magnetism and dielectric properties of this compound through coupling with the Mn spin structure.","abstract_html":"The following dissertation applies synchrotron radiation-based characterization techniques to the fields of gallium nitrides, multiferroic manganites, and self-assembled nano-domain oxide films. These material systems were chosen due to their unusual properties and potential device applications, which have made them very attractive to the scientific community. Synchrotron-based High Resolution X-ray Diffraction (HRXRD) was used to characterize the structural properties of GaN-based multiple quantum well (MQW) structures grown on trapezoidal shaped GaN ridges. Results where interpreted within the framework of vapor-phase diffusion and surface-migration effects during the metalorganic vapor phase epitaxial growth. The relatively short diffusion length of group- III precursors and growth enhancement, due to facet migration was found to have significant effects on the MQW formation. The use of synchrotron based HRXRD and in particular cross-sectional reciprocal space mapping (RSM) was then extended to studying the intriguing structural properties of a ZnMnGaO_4 film epitaxially grown on MgO (001) substrate. The results of this study helped in identifying the ZnMnGaO_4 film, as consisting of a self-assembled nano- checkerboard structure of highly aligned and regularly spaced vertical nanorods. The results demonstrated the importance of lattice distortion symmetry at the phase boundaries as a means for the coherent coexistence of two domain types within the film volume. Synchrotron-based far-infrared spectroscopy was performed at low temperatures on the single crystal multiferroic manganite HoMn_2O_5. A number of the infrared-active excitations were attributed to electric-dipole transitions between ligand-field split states of Ho^{3+} ions. It is proposed that the proximity in energy between magnons and Ho^{3+} ligand fields (LF) might connect the magnetism and dielectric properties of this compound through coupling with the Mn spin structure.","abstract_has_math":false,"creators":["O'Malley, Sean M."],"institution":null,"degree_name":"Doctor of Philosophy in Applied Physics - (Ph.D.)","degree_level":null,"degree_discipline":"Federated Physics Department","degree_department":null,"school":null,"contributors":["Andrei Sirenko","Daniel-Dennis McAlevy Bubb","John Francis Federici"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2009,"date_issued":"2009-01-31T08:00:00Z","date_published":"2009-01-31T08:00:00Z","updated_at":"2026-07-24T03:23:16Z","subjects":["Synchrotron","Multiferroic","Self-assembled","X-ray diffraction","Far-infrared spectroscopy","Group-III nitride","Other Physics"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.njit.edu/dissertations/896","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Andrei Sirenko","Daniel-Dennis McAlevy Bubb","John Francis Federici"]},{"key":"dc:creator","label":"Author","values":["O'Malley, Sean M."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:type","label":"Dc Type","values":["Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Federated Physics Department"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy in Applied Physics - (Ph.D.)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Synchrotron","Multiferroic","Self-assembled","X-ray diffraction","Far-infrared spectroscopy","Group-III nitride","Other Physics"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://digitalcommons.njit.edu/dissertations/896"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The following dissertation applies synchrotron radiation-based characterization techniques to the fields of gallium nitrides, multiferroic manganites, and self-assembled nano-domain oxide films. These material systems were chosen due to their unusual properties and potential device applications, which have made them very attractive to the scientific community. Synchrotron-based High Resolution X-ray Diffraction (HRXRD) was used to characterize the structural properties of GaN-based multiple quantum well (MQW) structures grown on trapezoidal shaped GaN ridges. Results where interpreted within the framework of vapor-phase diffusion and surface-migration effects during the metalorganic vapor phase epitaxial growth. The relatively short diffusion length of group- III precursors and growth enhancement, due to facet migration was found to have significant effects on the MQW formation. The use of synchrotron based HRXRD and in particular cross-sectional reciprocal space mapping (RSM) was then extended to studying the intriguing structural properties of a ZnMnGaO_4 film epitaxially grown on MgO (001) substrate. The results of this study helped in identifying the ZnMnGaO_4 film, as consisting of a self-assembled nano- checkerboard structure of highly aligned and regularly spaced vertical nanorods. The results demonstrated the importance of lattice distortion symmetry at the phase boundaries as a means for the coherent coexistence of two domain types within the film volume. Synchrotron-based far-infrared spectroscopy was performed at low temperatures on the single crystal multiferroic manganite HoMn_2O_5. A number of the infrared-active excitations were attributed to electric-dipole transitions between ligand-field split states of Ho^{3+} ions. It is proposed that the proximity in energy between magnons and Ho^{3+} ligand fields (LF) might connect the magnetism and dielectric properties of this compound through coupling with the Mn spin structure."]},{"key":"dc:title","label":"Title","values":["Synchrotron radiation-based characterization of GaN- based MQW structures and strongly correlated materials"]}]}],"canonical_facts":{"dc:contributor":["Andrei Sirenko","Daniel-Dennis McAlevy Bubb","John Francis Federici"],"dc:creator":["O'Malley, Sean M."],"dc:description.abstract":["The following dissertation applies synchrotron radiation-based characterization techniques to the fields of gallium nitrides, multiferroic manganites, and self-assembled nano-domain oxide films. These material systems were chosen due to their unusual properties and potential device applications, which have made them very attractive to the scientific community. Synchrotron-based High Resolution X-ray Diffraction (HRXRD) was used to characterize the structural properties of GaN-based multiple quantum well (MQW) structures grown on trapezoidal shaped GaN ridges. Results where interpreted within the framework of vapor-phase diffusion and surface-migration effects during the metalorganic vapor phase epitaxial growth. The relatively short diffusion length of group- III precursors and growth enhancement, due to facet migration was found to have significant effects on the MQW formation. The use of synchrotron based HRXRD and in particular cross-sectional reciprocal space mapping (RSM) was then extended to studying the intriguing structural properties of a ZnMnGaO_4 film epitaxially grown on MgO (001) substrate. The results of this study helped in identifying the ZnMnGaO_4 film, as consisting of a self-assembled nano- checkerboard structure of highly aligned and regularly spaced vertical nanorods. The results demonstrated the importance of lattice distortion symmetry at the phase boundaries as a means for the coherent coexistence of two domain types within the film volume. Synchrotron-based far-infrared spectroscopy was performed at low temperatures on the single crystal multiferroic manganite HoMn_2O_5. A number of the infrared-active excitations were attributed to electric-dipole transitions between ligand-field split states of Ho^{3+} ions. It is proposed that the proximity in energy between magnons and Ho^{3+} ligand fields (LF) might connect the magnetism and dielectric properties of this compound through coupling with the Mn spin structure."],"dc:identifier":["https://digitalcommons.njit.edu/dissertations/896"],"dc:subject":["Synchrotron","Multiferroic","Self-assembled","X-ray diffraction","Far-infrared spectroscopy","Group-III nitride","Other Physics"],"dc:title":["Synchrotron radiation-based characterization of GaN- based MQW structures and strongly correlated materials"],"dc:type":["Dissertation"],"thesis:degree_discipline":["Federated Physics Department"],"thesis:degree_name":["Doctor of Philosophy in Applied Physics - (Ph.D.)"]},"updated_at":"2026-07-24T03:23:16Z"}