{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/23069"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/23069","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Long wavelength infrared detectors utilizing multiple quantum wells in III-V compound semiconductors","abstract":"Data are presented on various infrared detectors based on multiple GaAs/AlGaAs quantum wells. Due to the great flexibility in the growth, dimensions, and composition of these structures, the electrical and optical characteristics of the photodetector may be significantly altered. This investigation explores both theoretically and experimentally the effect of modifying the well and barrier parameters.","abstract_html":"Data are presented on various infrared detectors based on multiple GaAs/AlGaAs quantum wells. Due to the great flexibility in the growth, dimensions, and composition of these structures, the electrical and optical characteristics of the photodetector may be significantly altered. This investigation explores both theoretically and experimentally the effect of modifying the well and barrier parameters.","abstract_has_math":false,"creators":["Dodd, Mark Alan"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Electrical Engineering","degree_department":null,"school":null,"contributors":["Stillman, Gregory E."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T14:01:02Z","date_published":"2011-05-07T14:01:02Z","updated_at":"2026-07-22T22:25:21Z","subjects":["Engineering, Electronics and Electrical","Physics, Electricity and Magnetism","Physics, Radiation"],"languages":["eng"],"rights":["Copyright 1994 Dodd, Mark Alan"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9503177","(UMI)AAI9503177"],"render_values":[{"text":"AAI9503177","href":null,"code":true},{"text":"(UMI)AAI9503177","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/23069","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Stillman, Gregory E."]},{"key":"dc:creator","label":"Author","values":["Dodd, Mark Alan"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T14:01:02Z","10000-01-01","1994"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"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":["Engineering, Electronics and Electrical","Physics, Electricity and Magnetism","Physics, Radiation"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1994 Dodd, Mark Alan"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9503177","(UMI)AAI9503177","http://hdl.handle.net/2142/23069"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Data are presented on various infrared detectors based on multiple GaAs/AlGaAs quantum wells. Due to the great flexibility in the growth, dimensions, and composition of these structures, the electrical and optical characteristics of the photodetector may be significantly altered. This investigation explores both theoretically and experimentally the effect of modifying the well and barrier parameters.","As GaAs/AlGaAs-based materials are prevalent in optical generation devices such as LEDs and lasers, it is natural to explore these materials' use for optical receivers as well. While most LEDs and lasers operate in the visible and near infrared (less than one micrometer), structures can operate to detect radiation with longer wavelengths. The simplest method to achieve longer wavelength absorption is through the use of quantum mechanical wells and their associated bound energy states. The energy level of the bound state may be changed by altering the well width or barrier composition. This allows one to tune the spectral response of the photodetector for a given application.","Three fundamental classes of quantum well infrared detectors (QWIDs) are examined. Each of these n-type, well-doped structures has its merits and drawbacks. The bound-to-bound state energy class is shown to have low dark current but also low responsivity. The bound-to-continuum class results in high dark current, high responsivity detectors. The bound-to-miniband QWIDs have low dark currents and moderate responsivity.","All three classes are explored in greater detail in an effort to increase responsivity. This was accomplished by altering the doping profile of the fundamental structure to include doping of the barrier. The results indicate that a factor of six increase is possible for the bound-to-continuum structure. An increase in operating temperature is an additional benefit of the revised doping profile.","As QWIDs do not typically respond to normally incident radiation, an optical grating must be used to couple the radiation so that it may be absorbed. A variety of one- and two-dimensional gratings are studied, and their impact on performance is reported. The fabrication technique used to form the grating is also examined. A deposited metal grating with a thin gold overcoat was found to yield the most efficient coupling and, therefore, the highest responsivity.","Made available in DSpace on 2011-05-07T14:01:02Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9503177.pdf: 5011422 bytes, checksum: 60014c58215e2e13b6705199c73868ef (MD5) Previous issue date: 1994","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:01:58Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:29:26-05:00 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":["Long wavelength infrared detectors utilizing multiple quantum wells in III-V compound semiconductors"]}]}],"canonical_facts":{"dc:contributor":["Stillman, Gregory E."],"dc:creator":["Dodd, Mark Alan"],"dc:date":["2011-05-07T14:01:02Z","10000-01-01","1994"],"dc:description":["Data are presented on various infrared detectors based on multiple GaAs/AlGaAs quantum wells. Due to the great flexibility in the growth, dimensions, and composition of these structures, the electrical and optical characteristics of the photodetector may be significantly altered. This investigation explores both theoretically and experimentally the effect of modifying the well and barrier parameters.","As GaAs/AlGaAs-based materials are prevalent in optical generation devices such as LEDs and lasers, it is natural to explore these materials' use for optical receivers as well. While most LEDs and lasers operate in the visible and near infrared (less than one micrometer), structures can operate to detect radiation with longer wavelengths. The simplest method to achieve longer wavelength absorption is through the use of quantum mechanical wells and their associated bound energy states. The energy level of the bound state may be changed by altering the well width or barrier composition. This allows one to tune the spectral response of the photodetector for a given application.","Three fundamental classes of quantum well infrared detectors (QWIDs) are examined. Each of these n-type, well-doped structures has its merits and drawbacks. The bound-to-bound state energy class is shown to have low dark current but also low responsivity. The bound-to-continuum class results in high dark current, high responsivity detectors. The bound-to-miniband QWIDs have low dark currents and moderate responsivity.","All three classes are explored in greater detail in an effort to increase responsivity. This was accomplished by altering the doping profile of the fundamental structure to include doping of the barrier. The results indicate that a factor of six increase is possible for the bound-to-continuum structure. An increase in operating temperature is an additional benefit of the revised doping profile.","As QWIDs do not typically respond to normally incident radiation, an optical grating must be used to couple the radiation so that it may be absorbed. A variety of one- and two-dimensional gratings are studied, and their impact on performance is reported. The fabrication technique used to form the grating is also examined. A deposited metal grating with a thin gold overcoat was found to yield the most efficient coupling and, therefore, the highest responsivity.","Made available in DSpace on 2011-05-07T14:01:02Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9503177.pdf: 5011422 bytes, checksum: 60014c58215e2e13b6705199c73868ef (MD5) Previous issue date: 1994","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:01:58Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:29:26-05:00 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":["AAI9503177","(UMI)AAI9503177","http://hdl.handle.net/2142/23069"],"dc:language":["eng"],"dc:rights":["Copyright 1994 Dodd, Mark Alan"],"dc:subject":["Engineering, Electronics and Electrical","Physics, Electricity and Magnetism","Physics, Radiation"],"dc:title":["Long wavelength infrared detectors utilizing multiple quantum wells in III-V compound semiconductors"],"dc:type":["text"],"thesis:degree_discipline":["Electrical Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:21Z"}