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dc.contributor.advisorHu, Evelynen_US
dc.contributor.authorWoolf, Alexander J.en_US
dc.date.accessioned2015-03-18T13:09:58Z
dc.date.created2015-03en_US
dc.date.issued2014-11-21en_US
dc.date.submitted2015en_US
dc.identifier.citationWoolf, Alexander J. 2015. Low-Threshold Indium Gallium Nitride Quantum Dot Microcavity Lasers. Doctoral dissertation, Harvard University, Graduate School of Arts & Sciences.en_US
dc.identifier.urihttp://nrs.harvard.edu/urn-3:HUL.InstRepos:14226080
dc.description.abstractGallium nitride (GaN) microcavities with embedded optical emitters have long been sought after as visible light sources as well as platforms for cavity quantum electrodynamics (cavity QED) experiments. Specifically, materials containing indium gallium nitride (InGaN) quantum dots (QDs) offer an outstanding platform to study light matter interactions and realize practical devices, such as on-chip light emitting diodes and nanolasers. Inherent advantages of nitride-based microcavities include low surface recombination velocities, enhanced room-temperature performance (due to their high exciton binding energy, as high as 67 meV for InGaN QDs), and emission wavelengths in the blue region of the visible spectrum. In spite of these advantages, several challenges must be overcome in order to capitalize on the potential of this material system. Such diffculties include the processing of GaN into high-quality devices due to the chemical inertness of the material, low material quality as a result of strain-induced defects, reduced carrier recombination effciencies due to internal fields, and a lack of characterization of the InGaN QDs themselves due to the diffculty of their growth and therefore lack of development relative to other semiconductor QDs. In this thesis we seek to understand and address such issues by investigating the interaction of light coupled to InGaN QDs via a GaN microcavity resonator. Such coupling led us to the demonstration of the first InGaN QD microcavity laser, whose performance offers insights into the properties and current limitations of the nitride materials and their emitters. This work is organized into three main sections. Part I outlines the key advantages and challenges regarding indium gallium nitride (InGaN) emitters embedded within gallium nitride (GaN) optical microcavities. Previous work is also discussed which establishes context for the work presented here. Part II includes the fundamentals related to laser operation, including the derivation and analysis of the laser rate equations. A thorough examination of the rate equations serves as a natural motivation for QDs and high-quality factor low-modal volume resonators as an optimal laser gain medium and cavity, respectively. The combination of the two theoretically yields the most efficient semiconductor laser device possible. Part III describes in detail the design, growth, fabrication and characterization of the first InGaN QD microcavity laser. Additional experiments are also conducted in order to conclusively prove that the InGaN QDs serve as the gain medium and facilitate laser oscillation within the microdisk cavities. Part III continues with work related towards the development of the next generation of nitride light emitting devices. This includes the realization of photonic crystal cavity (PCC) fragmented quantum well (FQW) lasers that exhibit record low lasing thresholds of 9.1 uJ/cm2, comparable to the best devices in other III-V material systems. Part III also discusses cavity QED experiments on InGaN QDs embedded within GaN PCCs in order to quantify the degree of light-matter interaction. The lack of experimental evidence for weak or strong coupling, in the form of the Purcell Effect or cavity-mode anti-crossing respectively, naturally motivates the question of what mechanism is limiting the device performance. Part III concludes with cathodoluminesence and tapered fiber measurements in order to identify the limiting factor towards achieving strong coupling between InGaN QDs and GaN microcavities.en_US
dc.format.mimetypeapplication/pdfen_US
dc.language.isoenen_US
dash.licenseLAAen_US
dc.subjectPhysics, Opticsen_US
dc.titleLow-Threshold Indium Gallium Nitride Quantum Dot Microcavity Lasersen_US
dc.typeThesis or Dissertationen_US
dash.depositing.authorWoolf, Alexander J.en_US
dc.date.available2015-03-18T13:09:58Z
thesis.degree.date2015en_US
thesis.degree.grantorGraduate School of Arts & Sciencesen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophyen_US
dc.contributor.committeeMemberCapasso, Federicoen_US
dc.contributor.committeeMemberMarko, Loncaren_US
dc.type.materialtexten_US
thesis.degree.departmentEngineering and Applied Sciences - Applied Physicsen_US
dash.identifier.vireohttp://etds.lib.harvard.edu/gsas/admin/view/50en_US
dc.description.keywordsgallium nitride; laser; microdisk; quantum dot; GaN; InGaN;en_US
dash.author.emailawoolf5000@gmail.comen_US
dash.identifier.drsurn-3:HUL.DRS.OBJECT:25119275en_US
dash.contributor.affiliatedWoolf, Alexander J


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