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Christopher A. Schuh. Peykov, Daniel Massachusetts Institute of Technology. Department of Materials Science and Engineering. Massachusetts Institute of Technology. Department of Materials Science and Engineering 2015-01-20T15:29:59Z 2015-01-20T15:29:59Z 2014 2014 http://hdl.handle.net/1721.1/92960 899267623 Thesis: S.M., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2014. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. Cataloged from student-submitted PDF version of thesis. Includes bibliographical references (pages 60-64). Photonic crystals offer an unparalleled control over optical properties and are ideal candidates as high efficiency selective emitters. They are, however, known to degrade at elevated temperatures through a number of processes, with one of the most notable being surface evolution by capillary forces. By comprehensively simulating the morphological and optical effects of this phenomenon, in the form of surface diffusion, vapor transport, and grain boundary grooving, this thesis seeks to understand its consequences and attempts to pinpoint methodologies that may prevent it. It was shown that while grain boundary grooves have a negligible effect on photonic crystal structures, vapor transport and surface diffusion may be significant. Indeed, vapor transport was found to progressively reduce the dimensions of photonic crystal cavities, and thus slightly alter their optical properties. Conversely, surface diffusion gradually closed o these cavities, thereby eliminating coupling into their resonant modes, and eradicating their selective emission capabilities. Changes to the shape of these photonic crystal structures that decreased their curvature and removed discontinuities were found to be beneficial in inhibiting degradation by capillarity, and an optimized structure that displays both higher efficiency and greater stability over time was ultimately theorized. by Daniel Peykov. S.M. 64 pages eng Massachusetts Institute of Technology 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. http://dspace.mit.edu/handle/1721.1/7582 Materials Science and Engineering. The effects of capillarity on photonic crystal selective emitters Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="cf500dfd-6e23-4941-838b-fc3bbb9bd39d"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>The effects of capillarity on photonic crystal selective emitters</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2014</PublicationDate> <Authors> <Author> <DisplayName>Peykov, Daniel</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Materials Science and Engineering.</Keyword> <Abstract>Photonic crystals offer an unparalleled control over optical properties and are ideal candidates as high efficiency selective emitters. They are, however, known to degrade at elevated temperatures through a number of processes, with one of the most notable being surface evolution by capillary forces. By comprehensively simulating the morphological and optical effects of this phenomenon, in the form of surface diffusion, vapor transport, and grain boundary grooving, this thesis seeks to understand its consequences and attempts to pinpoint methodologies that may prevent it. It was shown that while grain boundary grooves have a negligible effect on photonic crystal structures, vapor transport and surface diffusion may be significant. Indeed, vapor transport was found to progressively reduce the dimensions of photonic crystal cavities, and thus slightly alter their optical properties. Conversely, surface diffusion gradually closed o these cavities, thereby eliminating coupling into their resonant modes, and eradicating their selective emission capabilities. Changes to the shape of these photonic crystal structures that decreased their curvature and removed discontinuities were found to be beneficial in inhibiting degradation by capillarity, and an optimized structure that displays both higher efficiency and greater stability over time was ultimately theorized.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>