No Cover Image

E-Thesis 104 views 101 downloads

Numerical simulation of multiquantum barriers in 630nm laser diodes. / Martyn Rowan Brown

Swansea University Author: Martyn Rowan Brown

Abstract

Red-emitting quantum well (QW) 630nm laser diodes have many potential applications in industry and medicine. The main profiteers would be in areas such as the development of critical memory, barcode readers and in the treatment of cancer. The limitation of the low inherent band offsets of the materi...

Full description

Published: 2004
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
URI: https://cronfa.swan.ac.uk/Record/cronfa42417
Tags: Add Tag
No Tags, Be the first to tag this record!
first_indexed 2018-08-02T18:54:39Z
last_indexed 2018-08-03T10:10:05Z
id cronfa42417
recordtype RisThesis
fullrecord <?xml version="1.0"?><rfc1807><datestamp>2018-08-02T16:24:29.1817940</datestamp><bib-version>v2</bib-version><id>42417</id><entry>2018-08-02</entry><title>Numerical simulation of multiquantum barriers in 630nm laser diodes.</title><swanseaauthors><author><sid>8838f246c08ca85e2efc32eb07be634f</sid><ORCID>NULL</ORCID><firstname>Martyn Rowan</firstname><surname>Brown</surname><name>Martyn Rowan Brown</name><active>true</active><ethesisStudent>true</ethesisStudent></author></swanseaauthors><date>2018-08-02</date><abstract>Red-emitting quantum well (QW) 630nm laser diodes have many potential applications in industry and medicine. The main profiteers would be in areas such as the development of critical memory, barcode readers and in the treatment of cancer. The limitation of the low inherent band offsets of the materials used to create such devices, gives rise to a high percentage of electron leakage via thermal activation in the QW active region. However, implementation of Multiquantum Barrier (MQB) into the p-type cladding region of the device enhances the effective conduction band discontinuity, thus increasing the reflection probability of carriers back into the device active region, consequently elevating output power of the laser device. A study of (Al[0.7].Ga[0.3])[0.5]ln[0.5]P/(Al[0.3]Ga[0.7])[0.5]ln[0.5]P (barrier/well) MQB has been investigated as a feasible material structure to enhance electron confinement within laser diodes in the 630nm regime. The structure was optimised theoretically based on the Gamma-X transport mechanisms, using an effective mass approximation and the transfer matrix technique. To accurately model such structures it is important to include possible distortion to the conduction band profiles induced by the different positions of the Fermi level with respect to the vacuum level. Thus, a dual-band device simulator was developed to model the band bending features, of both the Gamma and X minima. This novel simulator simultaneously solves the constituent expressions making up the drift-diffusion equation set, which is then solved iteratively with Schrodinger's equation to yield a self-consistent solution. Using these two simulation models a novel MQB structure is proposed which inhibits electron transmission across it in both the Gamma and X bands. Subsequently, this MQB structure predicts a theoretical effective enhancements of 50% the height of the intrinsic conduction band offset.</abstract><type>E-Thesis</type><journal/><journalNumber></journalNumber><paginationStart/><paginationEnd/><publisher/><placeOfPublication/><isbnPrint/><issnPrint/><issnElectronic/><keywords>Applied physics.;Optics.</keywords><publishedDay>31</publishedDay><publishedMonth>12</publishedMonth><publishedYear>2004</publishedYear><publishedDate>2004-12-31</publishedDate><doi/><url/><notes/><college>COLLEGE NANME</college><department>Engineering</department><CollegeCode>COLLEGE CODE</CollegeCode><institution>Swansea University</institution><degreelevel>Doctoral</degreelevel><degreename>Ph.D</degreename><apcterm/><lastEdited>2018-08-02T16:24:29.1817940</lastEdited><Created>2018-08-02T16:24:29.1817940</Created><path><level id="1">Faculty of Science and Engineering</level><level id="2">School of Engineering and Applied Sciences - Uncategorised</level></path><authors><author><firstname>Martyn Rowan</firstname><surname>Brown</surname><orcid>NULL</orcid><order>1</order></author></authors><documents><document><filename>0042417-02082018162452.pdf</filename><originalFilename>10798125.pdf</originalFilename><uploaded>2018-08-02T16:24:52.7530000</uploaded><type>Output</type><contentLength>16623495</contentLength><contentType>application/pdf</contentType><version>E-Thesis</version><cronfaStatus>true</cronfaStatus><embargoDate>2018-08-02T16:24:52.7530000</embargoDate><copyrightCorrect>false</copyrightCorrect></document></documents><OutputDurs/></rfc1807>
spelling 2018-08-02T16:24:29.1817940 v2 42417 2018-08-02 Numerical simulation of multiquantum barriers in 630nm laser diodes. 8838f246c08ca85e2efc32eb07be634f NULL Martyn Rowan Brown Martyn Rowan Brown true true 2018-08-02 Red-emitting quantum well (QW) 630nm laser diodes have many potential applications in industry and medicine. The main profiteers would be in areas such as the development of critical memory, barcode readers and in the treatment of cancer. The limitation of the low inherent band offsets of the materials used to create such devices, gives rise to a high percentage of electron leakage via thermal activation in the QW active region. However, implementation of Multiquantum Barrier (MQB) into the p-type cladding region of the device enhances the effective conduction band discontinuity, thus increasing the reflection probability of carriers back into the device active region, consequently elevating output power of the laser device. A study of (Al[0.7].Ga[0.3])[0.5]ln[0.5]P/(Al[0.3]Ga[0.7])[0.5]ln[0.5]P (barrier/well) MQB has been investigated as a feasible material structure to enhance electron confinement within laser diodes in the 630nm regime. The structure was optimised theoretically based on the Gamma-X transport mechanisms, using an effective mass approximation and the transfer matrix technique. To accurately model such structures it is important to include possible distortion to the conduction band profiles induced by the different positions of the Fermi level with respect to the vacuum level. Thus, a dual-band device simulator was developed to model the band bending features, of both the Gamma and X minima. This novel simulator simultaneously solves the constituent expressions making up the drift-diffusion equation set, which is then solved iteratively with Schrodinger's equation to yield a self-consistent solution. Using these two simulation models a novel MQB structure is proposed which inhibits electron transmission across it in both the Gamma and X bands. Subsequently, this MQB structure predicts a theoretical effective enhancements of 50% the height of the intrinsic conduction band offset. E-Thesis Applied physics.;Optics. 31 12 2004 2004-12-31 COLLEGE NANME Engineering COLLEGE CODE Swansea University Doctoral Ph.D 2018-08-02T16:24:29.1817940 2018-08-02T16:24:29.1817940 Faculty of Science and Engineering School of Engineering and Applied Sciences - Uncategorised Martyn Rowan Brown NULL 1 0042417-02082018162452.pdf 10798125.pdf 2018-08-02T16:24:52.7530000 Output 16623495 application/pdf E-Thesis true 2018-08-02T16:24:52.7530000 false
title Numerical simulation of multiquantum barriers in 630nm laser diodes.
spellingShingle Numerical simulation of multiquantum barriers in 630nm laser diodes.
Martyn Rowan Brown
title_short Numerical simulation of multiquantum barriers in 630nm laser diodes.
title_full Numerical simulation of multiquantum barriers in 630nm laser diodes.
title_fullStr Numerical simulation of multiquantum barriers in 630nm laser diodes.
title_full_unstemmed Numerical simulation of multiquantum barriers in 630nm laser diodes.
title_sort Numerical simulation of multiquantum barriers in 630nm laser diodes.
author_id_str_mv 8838f246c08ca85e2efc32eb07be634f
author_id_fullname_str_mv 8838f246c08ca85e2efc32eb07be634f_***_Martyn Rowan Brown
author Martyn Rowan Brown
author2 Martyn Rowan Brown
format E-Thesis
publishDate 2004
institution Swansea University
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Engineering and Applied Sciences - Uncategorised{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Engineering and Applied Sciences - Uncategorised
document_store_str 1
active_str 0
description Red-emitting quantum well (QW) 630nm laser diodes have many potential applications in industry and medicine. The main profiteers would be in areas such as the development of critical memory, barcode readers and in the treatment of cancer. The limitation of the low inherent band offsets of the materials used to create such devices, gives rise to a high percentage of electron leakage via thermal activation in the QW active region. However, implementation of Multiquantum Barrier (MQB) into the p-type cladding region of the device enhances the effective conduction band discontinuity, thus increasing the reflection probability of carriers back into the device active region, consequently elevating output power of the laser device. A study of (Al[0.7].Ga[0.3])[0.5]ln[0.5]P/(Al[0.3]Ga[0.7])[0.5]ln[0.5]P (barrier/well) MQB has been investigated as a feasible material structure to enhance electron confinement within laser diodes in the 630nm regime. The structure was optimised theoretically based on the Gamma-X transport mechanisms, using an effective mass approximation and the transfer matrix technique. To accurately model such structures it is important to include possible distortion to the conduction band profiles induced by the different positions of the Fermi level with respect to the vacuum level. Thus, a dual-band device simulator was developed to model the band bending features, of both the Gamma and X minima. This novel simulator simultaneously solves the constituent expressions making up the drift-diffusion equation set, which is then solved iteratively with Schrodinger's equation to yield a self-consistent solution. Using these two simulation models a novel MQB structure is proposed which inhibits electron transmission across it in both the Gamma and X bands. Subsequently, this MQB structure predicts a theoretical effective enhancements of 50% the height of the intrinsic conduction band offset.
published_date 2004-12-31T03:52:55Z
_version_ 1763752621702643712
score 11.016258

Similar Items