{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/117592"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/117592","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Absolute internal quantum efficiency of indium-gallium nitride based light-emitting diodes","abstract":"Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-12-01","abstract_html":"Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-12-01","abstract_has_math":false,"creators":["Chiu, Yu-Chieh"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Electrical & Computer Engr","degree_department":null,"school":null,"contributors":["Bayram, Can"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022-12","date_published":"2022-12","updated_at":"2026-07-22T22:24:56Z","subjects":["Internal Quantum Efficiency","Light-emitting Diode","Photonics","Iii-nitride"],"languages":["en","eng"],"rights":["Copyright 2022 Yu-Chieh Chiu"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/117592","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Bayram, Can"]},{"key":"dc:creator","label":"Author","values":["Chiu, Yu-Chieh"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2022-12","2022-12-05"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical & Computer Engr"]},{"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":["Internal Quantum Efficiency","Light-emitting Diode","Photonics","Iii-nitride"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en","eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2022 Yu-Chieh Chiu"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/117592"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-12-01","The student, Yu-Chieh Chiu, accepted the attached license on 2022-12-01 at 13:26.","The student, Yu-Chieh Chiu, submitted this Thesis for approval on 2022-12-01 at 15:00.","This Thesis was approved for publication on 2022-12-05 at 16:37.","DSpace SAF Submission Ingestion Package generated from Vireo submission #18718 on 2023-04-12 at 11:36:42","This thesis presents a method to the reveal the absolute internal quantum efficiency of InGaN-based light-emitting diodes (LEDs). InGaN-based light emitting diodes are the backbone of modern high efficiency solid-state lighting, with emerging applications in areas such as next-generation displays for augmented and virtual reality (AR/VR), visible light communications, and bio-optoelectronics. Out of all the quantitative metrics used to characterize LEDs, efficiency is one of the key metrics. State-of-art blue LEDs reach >70% power conversion efficiency from electrical to optical power, but continual improvements are needed to achieve the Department of Energy’s projected efficiency goals, allowing for more energy and CO2 emission savings. Internal quantum efficiency (IQE) is one of many constituent efficiency metrics; it sets the upper-bound of efficiency and is affected by material quality (e.g. defect density) and stack design (e.g. layer thickness). Despite the importance of IQE, there are challenges and possibly erroneous assumptions with current techniques used to measure it. This thesis will first provide an overview of LEDs, including operational principles, efficiency metrics, and a need for an absolute efficiency metric. Next, the theoretical formulation of the method to determine the absolute IQE is discussed, followed by a brief interlude on experimental setup. The structural properties of the LEDs are studied via optical, scanning electron, and atomic force microscopies, X-Ray diffraction, and Raman spectroscopy. Next, optical (via temperature-, time- and power- dependent photoluminescence) properties of InGaN-based blue LEDs are coupled with a channel-based recombination model, to determine the absolute IQE of the LEDs and correlate with their respective structural properties."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Absolute internal quantum efficiency of indium-gallium nitride based light-emitting diodes"]}]}],"canonical_facts":{"dc:contributor":["Bayram, Can"],"dc:creator":["Chiu, Yu-Chieh"],"dc:date":["2022-12","2022-12-05"],"dc:description":["Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-12-01","The student, Yu-Chieh Chiu, accepted the attached license on 2022-12-01 at 13:26.","The student, Yu-Chieh Chiu, submitted this Thesis for approval on 2022-12-01 at 15:00.","This Thesis was approved for publication on 2022-12-05 at 16:37.","DSpace SAF Submission Ingestion Package generated from Vireo submission #18718 on 2023-04-12 at 11:36:42","This thesis presents a method to the reveal the absolute internal quantum efficiency of InGaN-based light-emitting diodes (LEDs). InGaN-based light emitting diodes are the backbone of modern high efficiency solid-state lighting, with emerging applications in areas such as next-generation displays for augmented and virtual reality (AR/VR), visible light communications, and bio-optoelectronics. Out of all the quantitative metrics used to characterize LEDs, efficiency is one of the key metrics. State-of-art blue LEDs reach >70% power conversion efficiency from electrical to optical power, but continual improvements are needed to achieve the Department of Energy’s projected efficiency goals, allowing for more energy and CO2 emission savings. Internal quantum efficiency (IQE) is one of many constituent efficiency metrics; it sets the upper-bound of efficiency and is affected by material quality (e.g. defect density) and stack design (e.g. layer thickness). Despite the importance of IQE, there are challenges and possibly erroneous assumptions with current techniques used to measure it. This thesis will first provide an overview of LEDs, including operational principles, efficiency metrics, and a need for an absolute efficiency metric. Next, the theoretical formulation of the method to determine the absolute IQE is discussed, followed by a brief interlude on experimental setup. The structural properties of the LEDs are studied via optical, scanning electron, and atomic force microscopies, X-Ray diffraction, and Raman spectroscopy. Next, optical (via temperature-, time- and power- dependent photoluminescence) properties of InGaN-based blue LEDs are coupled with a channel-based recombination model, to determine the absolute IQE of the LEDs and correlate with their respective structural properties."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/117592"],"dc:language":["en","eng"],"dc:rights":["Copyright 2022 Yu-Chieh Chiu"],"dc:subject":["Internal Quantum Efficiency","Light-emitting Diode","Photonics","Iii-nitride"],"dc:title":["Absolute internal quantum efficiency of indium-gallium nitride based light-emitting diodes"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Electrical & Computer Engr"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:56Z"}