{"id":{"repo_id":"mit","oai_identifier":"oai:dspace.mit.edu:1721.1/27869"},"canonical_url":"https://search.dev.ndltd.org/etd/mit/oai:dspace.mit.edu:1721.1/27869","repository":{"repo_id":"mit","name":"MIT","base_url":"https://dspace.mit.edu/oai/request"},"display":{"title":"A quantum dot heterojunction photodetector","abstract":"This thesis presents a new device architecture for photodetectors utilizing colloidally grown quantum dots as the principle photo-active component. We implement a thin film of cadmium selenide (CdSe) quantum dot sensitizers, sandwiched between an electron-transporting titanium dioxide (TiO2) layer and a hole-transporting N,N' diphenyl-N,N' bis(3-ethylphenyl)-(1,1'-biphenyl)- 4,4'-diamine (TPD) organic small molecule layer. The wide band gap TiO2 and TPD layers are found to block charge injection under reverse bias, yet serve as transport layers for photo-excited charge generated in the CdSe. The internal quantum efficiency is approximately 1% at zero bias and saturates at 3% at -1V. Current-voltage sweeps yield low dark current in reverse bias and significant hysteresis under illumination. We speculate that the hysteresis and low quantum efficiency are due to charge accumulation at the TiO2/CdSe interface.","abstract_html":"This thesis presents a new device architecture for photodetectors utilizing colloidally grown quantum dots as the principle photo-active component. We implement a thin film of cadmium selenide (CdSe) quantum dot sensitizers, sandwiched between an electron-transporting titanium dioxide (TiO2) layer and a hole-transporting N,N' diphenyl-N,N' bis(3-ethylphenyl)-(1,1'-biphenyl)- 4,4'-diamine (TPD) organic small molecule layer. The wide band gap TiO2 and TPD layers are found to block charge injection under reverse bias, yet serve as transport layers for photo-excited charge generated in the CdSe. The internal quantum efficiency is approximately 1% at zero bias and saturates at 3% at -1V. Current-voltage sweeps yield low dark current in reverse bias and significant hysteresis under illumination. We speculate that the hysteresis and low quantum efficiency are due to charge accumulation at the TiO2/CdSe interface.","abstract_has_math":false,"creators":["Arango, Alexi Cosmos, 1975-"],"institution":"Massachusetts Institute of Technology","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.","school":null,"contributors":[],"advisors":["Vladimir Bulović."],"committee_chairs":[],"committee_members":[],"year":2005,"date_issued":"2005","date_published":"2005","updated_at":"2026-07-22T22:21:38Z","subjects":["Electrical Engineering and Computer Science."],"languages":["en_US"],"rights":["M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission."],"rights_urls":["http://dspace.mit.edu/handle/1721.1/7582"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/1721.1/27869","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Vladimir Bulović."]},{"key":"dc:contributor.department","label":"Department","values":["Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science."]},{"key":"dc:contributor.other","label":"Dc Contributor Other","values":["Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science."]},{"key":"dc:creator","label":"Author","values":["Arango, Alexi Cosmos, 1975-"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2005-09-26T15:54:19Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2005-09-26T15:54:19Z"]},{"key":"dc:date.issued","label":"Date","values":["2005"]},{"key":"dc:publisher","label":"Institution","values":["Massachusetts Institute of Technology"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Electrical Engineering and Computer Science."]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en_US"]},{"key":"dc:rights","label":"Dc Rights","values":["M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission."]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://dspace.mit.edu/handle/1721.1/7582"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/1721.1/27869"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.","This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.","Includes bibliographical references (p. 113-119)."]},{"key":"dc:description.abstract","label":"Abstract","values":["This thesis presents a new device architecture for photodetectors utilizing colloidally grown quantum dots as the principle photo-active component. We implement a thin film of cadmium selenide (CdSe) quantum dot sensitizers, sandwiched between an electron-transporting titanium dioxide (TiO2) layer and a hole-transporting N,N' diphenyl-N,N' bis(3-ethylphenyl)-(1,1'-biphenyl)- 4,4'-diamine (TPD) organic small molecule layer. The wide band gap TiO2 and TPD layers are found to block charge injection under reverse bias, yet serve as transport layers for photo-excited charge generated in the CdSe. The internal quantum efficiency is approximately 1% at zero bias and saturates at 3% at -1V. Current-voltage sweeps yield low dark current in reverse bias and significant hysteresis under illumination. We speculate that the hysteresis and low quantum efficiency are due to charge accumulation at the TiO2/CdSe interface."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["S.M."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["A quantum dot heterojunction photodetector"]}]}],"canonical_facts":{"dc:contributor.advisor":["Vladimir Bulović."],"dc:contributor.department":["Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science."],"dc:contributor.other":["Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science."],"dc:creator":["Arango, Alexi Cosmos, 1975-"],"dc:date.accessioned":["2005-09-26T15:54:19Z"],"dc:date.available":["2005-09-26T15:54:19Z"],"dc:date.issued":["2005"],"dc:description":["Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.","This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.","Includes bibliographical references (p. 113-119)."],"dc:description.abstract":["This thesis presents a new device architecture for photodetectors utilizing colloidally grown quantum dots as the principle photo-active component. We implement a thin film of cadmium selenide (CdSe) quantum dot sensitizers, sandwiched between an electron-transporting titanium dioxide (TiO2) layer and a hole-transporting N,N' diphenyl-N,N' bis(3-ethylphenyl)-(1,1'-biphenyl)- 4,4'-diamine (TPD) organic small molecule layer. The wide band gap TiO2 and TPD layers are found to block charge injection under reverse bias, yet serve as transport layers for photo-excited charge generated in the CdSe. The internal quantum efficiency is approximately 1% at zero bias and saturates at 3% at -1V. Current-voltage sweeps yield low dark current in reverse bias and significant hysteresis under illumination. We speculate that the hysteresis and low quantum efficiency are due to charge accumulation at the TiO2/CdSe interface."],"dc:description.degree":["S.M."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["http://hdl.handle.net/1721.1/27869"],"dc:language.iso":["en_US"],"dc:publisher":["Massachusetts Institute of Technology"],"dc:rights":["M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission."],"dc:rights.uri":["http://dspace.mit.edu/handle/1721.1/7582"],"dc:subject":["Electrical Engineering and Computer Science."],"dc:title":["A quantum dot heterojunction photodetector"],"dc:type":["Thesis"]},"updated_at":"2026-07-22T22:21:38Z"}