{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/28691"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/28691","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Carrier relaxation in doped quantum wells","abstract":"The relaxation time of an electron in a quantum well is derived within the random-phase approximation including full multi-subband and frequency dependent screening. The resulting expression encompasses both electron-electron and electron-phonon scattering taking into account the mutual interactions of the electrons and phonons. The intersubband relaxation time of an electron is numerically evaluated considering electron-electron and electron-phonon (bulk LO-phonon) scattering in a GaAs quantum well. It is shown that the intersubband relaxation time is significantly influenced by the electron density in the well. It is also shown that at room temperature it is necessary to use the finite temperature dielectric function to accurately determine the intersubband relaxation time. Scattering due to the coupled system of electrons and phonons is compared with the decoupled scattering where both electron-electron and unscreened electron-phonon scattering are considered separately. In addition, the above theory of carrier relaxation is applied to quantum well lasers. The gain saturation coefficient, c:, of InxGat-xAs/ Alo.2Gao.8As strained layer quantum well lasers (SL-QWLs) is calculated as a function of strain from carrier intrasubband relaxation times. The intrasubband relaxation times are calculated within the RPA including carrier-carrier as well as carrier-polar optical phonon interactions at a temperature of 300 K. The band structures are determined from the Luttinger-Kohn Hamiltonian and a multiband effective mass equation. It is demonstrated that the gain saturation coefficient increases with compressive strain in the active layer of the quantum well due to a corresponding increase of the intrasubband relaxation time. From this, a direct connection between strain and laser switching speed can be deduced.","abstract_html":"The relaxation time of an electron in a quantum well is derived within the random-phase approximation including full multi-subband and frequency dependent screening. The resulting expression encompasses both electron-electron and electron-phonon scattering taking into account the mutual interactions of the electrons and phonons. The intersubband relaxation time of an electron is numerically evaluated considering electron-electron and electron-phonon (bulk LO-phonon) scattering in a GaAs quantum well. It is shown that the intersubband relaxation time is significantly influenced by the electron density in the well. It is also shown that at room temperature it is necessary to use the finite temperature dielectric function to accurately determine the intersubband relaxation time. Scattering due to the coupled system of electrons and phonons is compared with the decoupled scattering where both electron-electron and unscreened electron-phonon scattering are considered separately. In addition, the above theory of carrier relaxation is applied to quantum well lasers. The gain saturation coefficient, c:, of InxGat-xAs/ Alo.2Gao.8As strained layer quantum well lasers (SL-QWLs) is calculated as a function of strain from carrier intrasubband relaxation times. The intrasubband relaxation times are calculated within the RPA including carrier-carrier as well as carrier-polar optical phonon interactions at a temperature of 300 K. The band structures are determined from the Luttinger-Kohn Hamiltonian and a multiband effective mass equation. It is demonstrated that the gain saturation coefficient increases with compressive strain in the active layer of the quantum well due to a corresponding increase of the intrasubband relaxation time. From this, a direct connection between strain and laser switching speed can be deduced.","abstract_has_math":false,"creators":["Sotirelis, Paul Peter"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Hess, Karl"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2012,"date_issued":"2012-01-25T22:08:41Z","date_published":"2012-01-25T22:08:41Z","updated_at":"2026-07-22T22:25:27Z","subjects":["doped quantum wells","electron","carrier relaxation","quantum well laser"],"languages":["en"],"rights":["1993 Paul Peter Sotirelis"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/28691","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Hess, Karl"]},{"key":"dc:creator","label":"Author","values":["Sotirelis, Paul Peter"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2012-01-25T22:08:41Z","10000-01-01","1993"]},{"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":["doped quantum wells","electron","carrier relaxation","quantum well laser"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["1993 Paul Peter Sotirelis"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/28691"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The relaxation time of an electron in a quantum well is derived within the random-phase approximation including full multi-subband and frequency dependent screening. The resulting expression encompasses both electron-electron and electron-phonon scattering taking into account the mutual interactions of the electrons and phonons. The intersubband relaxation time of an electron is numerically evaluated considering electron-electron and electron-phonon (bulk LO-phonon) scattering in a GaAs quantum well. It is shown that the intersubband relaxation time is significantly influenced by the electron density in the well. It is also shown that at room temperature it is necessary to use the finite temperature dielectric function to accurately determine the intersubband relaxation time. Scattering due to the coupled system of electrons and phonons is compared with the decoupled scattering where both electron-electron and unscreened electron-phonon scattering are considered separately. In addition, the above theory of carrier relaxation is applied to quantum well lasers. The gain saturation coefficient, c:, of InxGat-xAs/ Alo.2Gao.8As strained layer quantum well lasers (SL-QWLs) is calculated as a function of strain from carrier intrasubband relaxation times. The intrasubband relaxation times are calculated within the RPA including carrier-carrier as well as carrier-polar optical phonon interactions at a temperature of 300 K. The band structures are determined from the Luttinger-Kohn Hamiltonian and a multiband effective mass equation. It is demonstrated that the gain saturation coefficient increases with compressive strain in the active layer of the quantum well due to a corresponding increase of the intrasubband relaxation time. From this, a direct connection between strain and laser switching speed can be deduced.","Submitted by Carolyn Rauber (crauber2@illinois.edu) on 2012-01-25T22:08:41Z No. of bitstreams: 1 1993_sotirelis.pdf: 1680296 bytes, checksum: e7b64a7f73093d128de626938057ba3f (MD5)","Made available in DSpace on 2012-01-25T22:08:41Z (GMT). No. of bitstreams: 1 1993_sotirelis.pdf: 1680296 bytes, checksum: e7b64a7f73093d128de626938057ba3f (MD5) Previous issue date: 1993","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Rauber (crauber2@illinois.edu) on 2012-01-25T22:08:41Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:10:14-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: dissertation","dissertation","U of I Only"]},{"key":"dc:title","label":"Title","values":["Carrier relaxation in doped quantum wells"]}]}],"canonical_facts":{"dc:contributor":["Hess, Karl"],"dc:creator":["Sotirelis, Paul Peter"],"dc:date":["2012-01-25T22:08:41Z","10000-01-01","1993"],"dc:description":["The relaxation time of an electron in a quantum well is derived within the random-phase approximation including full multi-subband and frequency dependent screening. The resulting expression encompasses both electron-electron and electron-phonon scattering taking into account the mutual interactions of the electrons and phonons. The intersubband relaxation time of an electron is numerically evaluated considering electron-electron and electron-phonon (bulk LO-phonon) scattering in a GaAs quantum well. It is shown that the intersubband relaxation time is significantly influenced by the electron density in the well. It is also shown that at room temperature it is necessary to use the finite temperature dielectric function to accurately determine the intersubband relaxation time. Scattering due to the coupled system of electrons and phonons is compared with the decoupled scattering where both electron-electron and unscreened electron-phonon scattering are considered separately. In addition, the above theory of carrier relaxation is applied to quantum well lasers. The gain saturation coefficient, c:, of InxGat-xAs/ Alo.2Gao.8As strained layer quantum well lasers (SL-QWLs) is calculated as a function of strain from carrier intrasubband relaxation times. The intrasubband relaxation times are calculated within the RPA including carrier-carrier as well as carrier-polar optical phonon interactions at a temperature of 300 K. The band structures are determined from the Luttinger-Kohn Hamiltonian and a multiband effective mass equation. It is demonstrated that the gain saturation coefficient increases with compressive strain in the active layer of the quantum well due to a corresponding increase of the intrasubband relaxation time. From this, a direct connection between strain and laser switching speed can be deduced.","Submitted by Carolyn Rauber (crauber2@illinois.edu) on 2012-01-25T22:08:41Z No. of bitstreams: 1 1993_sotirelis.pdf: 1680296 bytes, checksum: e7b64a7f73093d128de626938057ba3f (MD5)","Made available in DSpace on 2012-01-25T22:08:41Z (GMT). No. of bitstreams: 1 1993_sotirelis.pdf: 1680296 bytes, checksum: e7b64a7f73093d128de626938057ba3f (MD5) Previous issue date: 1993","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Rauber (crauber2@illinois.edu) on 2012-01-25T22:08:41Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:10:14-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: dissertation","dissertation","U of I Only"],"dc:identifier":["http://hdl.handle.net/2142/28691"],"dc:language":["en"],"dc:rights":["1993 Paul Peter Sotirelis"],"dc:subject":["doped quantum wells","electron","carrier relaxation","quantum well laser"],"dc:title":["Carrier relaxation in doped quantum wells"],"dc:type":["Dissertation / Thesis","text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-22T22:25:27Z"}