{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/25530"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/25530","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Study of exciton localized by random potential in indirect gallium arsenide phosphide alloys","abstract":"We have studied in detail a new structure Mx/0 in photoluminescence spectra from n-type indirect GaAs P alloys. The intensity of Mx/0 starts l -x x to saturate relative to that of the donor-bound exciton (Do) at very low excitation laser po\\vcr. It has a low activation energy (2 meV) and prominant X-point phonon sidebands. Its wave function is effective-mass-like and is associated with the X-point in K-space. We interpret the MO band as due to excitons localized by the random potentials in the alloys. Lifetime measurements show that the Mx/0 excitons are relatively long lived (tens of microseconds) and it varies over the spectral regions of the M~ emission band. This can be understood in terms of the energy-dependence of the effective range of the excitons in the presence of impurity centers in the sample. Such characteristic is unique for the Anderson-type localized excitons. The valley-anisotropy (V-A) splitting of the localized exciton is directly observed under resonant excitation at Mx/0. The lineshape of the enhancement curves of a prolllinent longitudinal accoustic phonon (LAX) side- band of Mx/0 changes with temperature. This provides information which is necessary for the identification of the V-A split excited state. The pseudo-extended nature of the excited state plays an important role in the low activation energy of Mx/0. The asymmetric lineshape of Mx/0 is qualitatively explained.","abstract_html":"We have studied in detail a new structure Mx/0 in photoluminescence spectra from n-type indirect GaAs P alloys. The intensity of Mx/0 starts l -x x to saturate relative to that of the donor-bound exciton (Do) at very low excitation laser po\\vcr. It has a low activation energy (2 meV) and prominant X-point phonon sidebands. Its wave function is effective-mass-like and is associated with the X-point in K-space. We interpret the MO band as due to excitons localized by the random potentials in the alloys. Lifetime measurements show that the Mx/0 excitons are relatively long lived (tens of microseconds) and it varies over the spectral regions of the M~ emission band. This can be understood in terms of the energy-dependence of the effective range of the excitons in the presence of impurity centers in the sample. Such characteristic is unique for the Anderson-type localized excitons. The valley-anisotropy (V-A) splitting of the localized exciton is directly observed under resonant excitation at Mx/0. The lineshape of the enhancement curves of a prolllinent longitudinal accoustic phonon (LAX) side- band of Mx/0 changes with temperature. This provides information which is necessary for the identification of the V-A split excited state. The pseudo-extended nature of the excited state plays an important role in the low activation energy of Mx/0. The asymmetric lineshape of Mx/0 is qualitatively explained.","abstract_has_math":false,"creators":["Lai, Shui Tong"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Klein, Miles V."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-06-27T15:08:10Z","date_published":"2011-06-27T15:08:10Z","updated_at":"2026-07-22T22:25:24Z","subjects":["exciton","random potential","indirect gallium arsenide phosphide alloys","photoluminescence"],"languages":["en"],"rights":["1980 Shui Tong Lai"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["452695"],"render_values":[{"text":"452695","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/25530","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Klein, Miles V."]},{"key":"dc:creator","label":"Author","values":["Lai, Shui Tong"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-06-27T15:08:10Z","10000-01-01","1980"]},{"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":["exciton","random potential","indirect gallium arsenide phosphide alloys","photoluminescence"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["1980 Shui Tong Lai"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["452695","http://hdl.handle.net/2142/25530"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["We have studied in detail a new structure Mx/0 in photoluminescence spectra from n-type indirect GaAs P alloys. The intensity of Mx/0 starts l -x x to saturate relative to that of the donor-bound exciton (Do) at very low excitation laser po\\vcr. It has a low activation energy (2 meV) and prominant X-point phonon sidebands. Its wave function is effective-mass-like and is associated with the X-point in K-space. We interpret the MO band as due to excitons localized by the random potentials in the alloys. Lifetime measurements show that the Mx/0 excitons are relatively long lived (tens of microseconds) and it varies over the spectral regions of the M~ emission band. This can be understood in terms of the energy-dependence of the effective range of the excitons in the presence of impurity centers in the sample. Such characteristic is unique for the Anderson-type localized excitons. The valley-anisotropy (V-A) splitting of the localized exciton is directly observed under resonant excitation at Mx/0. The lineshape of the enhancement curves of a prolllinent longitudinal accoustic phonon (LAX) side- band of Mx/0 changes with temperature. This provides information which is necessary for the identification of the V-A split excited state. The pseudo-extended nature of the excited state plays an important role in the low activation energy of Mx/0. The asymmetric lineshape of Mx/0 is qualitatively explained.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-27T15:08:10Z No. of bitstreams: 1 1980_lai.pdf: 3281376 bytes, checksum: 80cdd3e04e3c8f81e5e43a7436521bc7 (MD5)","Made available in DSpace on 2011-06-27T15:08:10Z (GMT). No. of bitstreams: 1 1980_lai.pdf: 3281376 bytes, checksum: 80cdd3e04e3c8f81e5e43a7436521bc7 (MD5) Previous issue date: 1980","Restriction data tranferred 2014-07-01T11:32:23-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-06-27T15:08:10Z Item is restricted indefinitely.","Thesis","U of I Only"]},{"key":"dc:title","label":"Title","values":["Study of exciton localized by random potential in indirect gallium arsenide phosphide alloys"]}]}],"canonical_facts":{"dc:contributor":["Klein, Miles V."],"dc:creator":["Lai, Shui Tong"],"dc:date":["2011-06-27T15:08:10Z","10000-01-01","1980"],"dc:description":["We have studied in detail a new structure Mx/0 in photoluminescence spectra from n-type indirect GaAs P alloys. The intensity of Mx/0 starts l -x x to saturate relative to that of the donor-bound exciton (Do) at very low excitation laser po\\vcr. It has a low activation energy (2 meV) and prominant X-point phonon sidebands. Its wave function is effective-mass-like and is associated with the X-point in K-space. We interpret the MO band as due to excitons localized by the random potentials in the alloys. Lifetime measurements show that the Mx/0 excitons are relatively long lived (tens of microseconds) and it varies over the spectral regions of the M~ emission band. This can be understood in terms of the energy-dependence of the effective range of the excitons in the presence of impurity centers in the sample. Such characteristic is unique for the Anderson-type localized excitons. The valley-anisotropy (V-A) splitting of the localized exciton is directly observed under resonant excitation at Mx/0. The lineshape of the enhancement curves of a prolllinent longitudinal accoustic phonon (LAX) side- band of Mx/0 changes with temperature. This provides information which is necessary for the identification of the V-A split excited state. The pseudo-extended nature of the excited state plays an important role in the low activation energy of Mx/0. The asymmetric lineshape of Mx/0 is qualitatively explained.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-27T15:08:10Z No. of bitstreams: 1 1980_lai.pdf: 3281376 bytes, checksum: 80cdd3e04e3c8f81e5e43a7436521bc7 (MD5)","Made available in DSpace on 2011-06-27T15:08:10Z (GMT). No. of bitstreams: 1 1980_lai.pdf: 3281376 bytes, checksum: 80cdd3e04e3c8f81e5e43a7436521bc7 (MD5) Previous issue date: 1980","Restriction data tranferred 2014-07-01T11:32:23-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-06-27T15:08:10Z Item is restricted indefinitely.","Thesis","U of I Only"],"dc:identifier":["452695","http://hdl.handle.net/2142/25530"],"dc:language":["en"],"dc:rights":["1980 Shui Tong Lai"],"dc:subject":["exciton","random potential","indirect gallium arsenide phosphide alloys","photoluminescence"],"dc:title":["Study of exciton localized by random potential in indirect gallium arsenide phosphide alloys"],"dc:type":["Dissertation / Thesis","text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-22T22:25:24Z"}