東華大學圖書館 |

Silicon Nanowires as Templates for Hybrid Plasmonics and Advanced Photonics /

Record Type:	Electronic resources : Monograph/item
Title/Author:	Silicon Nanowires as Templates for Hybrid Plasmonics and Advanced Photonics // Corban Graef Edward Murphey.
Author:	Murphey, Corban Graef Edward,
Description:	1 electronic resource (126 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 85-11, Section: B.
Contained By:	Dissertations Abstracts International85-11B.
Subject:	Chemistry. -
Online resource:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30990182
ISBN:	9798382717036

Silicon Nanowires as Templates for Hybrid Plasmonics and Advanced Photonics /
Murphey, Corban Graef Edward,

Silicon Nanowires as Templates for Hybrid Plasmonics and Advanced Photonics /Corban Graef Edward Murphey. - 1 electronic resource (126 pages)

Source: Dissertations Abstracts International, Volume: 85-11, Section: B.

Confining light into a small space is a key aim in many areas of photonics research. If you try to do this with traditional optics, you quickly run into a fundamental limit: the Abbe diffraction limit. This dictates that a beam of light with wavelength λ can only be confined to a size of approximately λ/2. When working with visible or even ultraviolet light, this means it is very challenging to focus that beam into a space less than ~100 nm in size, and with modern technological components getting smaller and smaller each year, other means are necessary to confine light into small spaces. Two phenomena in particular have emerged as strategies for squeezing light down to the nanoscale: plasmon resonances and optical bound states in the continuum (BICs).Plasmon resonances, which are the result of collective oscillations of surface electrons at a metal-dielectric interface, are able to confine incident light to a deep-subwavelength, or less than λ/10, scale. However, since plasmonic nanomaterials often consist solely of metals, the rapid electron motion in the particle can result in large Ohmic losses, which results in sometimes undesirable heating effects, large spectral linewidths, and short surface plasmon polariton propagation lengths. In comparison, dielectric materials like Si have much lower losses and can sustain narrow linewidths and long propagation distances, but because of their low free carrier concentration, they are not generally able to confine light on the same sub-wavelength scale as metallic plasmonic materials. If these two classes of materials were combined into a single nanostructure, such that the electric field generated by the plasmon resonance were confined into a dielectric core, it would be possible to achieve simultaneous sub-wavelength confinement and low loss. We were able to synthesize such a structure-an epitaxial Si nanowire (NW) core coated with a shell of Au- via a combination of vapor-liquid-solid (VLS) NW growth and metal sputtering. Examining these hybrid NWs using both optical simulations and experimental extinction measurements, we found that they support Mie resonances with quality factors (Q-factors) enhanced up to ~30 times compared to pure dielectric structures and plasmon resonances with optical confinement enhanced up to ~5 times compared to pure metallic structures. We also show that the spectral response of the Mie and plasmon resonances can be reproduced with temporal coupled mode theory (TCMT) and the Fano lineshapes can be attributed to the combination of the high Q-factor resonances, Mie-plasmon coupling, and phase delay of the background optical field. Our work demonstrates a bottom-up method for synthesizing free-standing, cylindrically symmetric, core-shell nanowires that efficiently trap light on a deep sub-wavelength scale, which has implications for many applications in photonics and optoelectronics.As alluded to above, Si NWs have attracted significant attention recently due to their photonic properties, such as their ability to support axially guided optical modes. By periodically modulating dopant gas flow during VLS growth and then wet-chemical etching the as-grown NWs, we can create semi-infinite geometric superlattices, or GSLs. Under specific geometric parameters, Si NW GSLs can support BICs of different orders, which have theoretically infinite lifetimes and Q-factors, and are perfectly isolated from surrounding radiation. If one purposefully detunes those idealized geometric parameters, a quasi-BIC (qBIC) is formed. qBICs retain the high Q-factor and lifetimes of true BICs, but are able to couple with external radiation and manifest as absorption and scattering features. This allows for the identification of trends in different qBICs and their behavior with respect to other Si NW resonances, such as Mie resonances or other qBICs and BICs. We simulated and synthesized a suite of NW GSL geometries that support several qBICs in the visible through NIR spectral regions. Through analysis of the simulated electric and magnetic field profiles, we have also developed a labeling scheme to identify and track different modes across different parameters. We then experimentally detected these qBICs with two, home-built, single-nanowire spectroscopy apparatuses: one measuring extinction and the other measuring photothermal absorption. Our work demonstrates the ability to precisely control the presence, position, and properties of qBICs in Si NW GSLs, with the potential to enhance the ability of photovoltaic Si NWs to harvest the solar spectrum.

English

ISBN: 9798382717036Subjects--Topical Terms:

516420
Chemistry.
Subjects--Index Terms:

Chemical vapor deposition

Silicon Nanowires as Templates for Hybrid Plasmonics and Advanced Photonics /
LDR:06127nmm a22004573i 4500 001 2431874
005 20250624125401.5
006 m o d
007 cr|nu||||||||
008 261011s2024 miu||||||m |||||||eng d
020 $a 9798382717036
035 $a (MiAaPQD)AAI30990182
035 $a AAI30990182
040 $a MiAaPQD $b eng $c MiAaPQD $e rda
100 1 $a Murphey, Corban Graef Edward, $e author. $3 3820885
245 1 0 $a Silicon Nanowires as Templates for Hybrid Plasmonics and Advanced Photonics / $c Corban Graef Edward Murphey.
264 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2024
300 $a 1 electronic resource (126 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 85-11, Section: B.
500 $a Advisors: Cahoon, James F. Committee members: Warren, Scott C.; Atkin, Joanna M.; Lockett, Matthew R.; Geil, Robert D.
502 $b Ph.D. $c The University of North Carolina at Chapel Hill $d 2024.
520 $a Confining light into a small space is a key aim in many areas of photonics research. If you try to do this with traditional optics, you quickly run into a fundamental limit: the Abbe diffraction limit. This dictates that a beam of light with wavelength λ can only be confined to a size of approximately λ/2. When working with visible or even ultraviolet light, this means it is very challenging to focus that beam into a space less than ~100 nm in size, and with modern technological components getting smaller and smaller each year, other means are necessary to confine light into small spaces. Two phenomena in particular have emerged as strategies for squeezing light down to the nanoscale: plasmon resonances and optical bound states in the continuum (BICs).Plasmon resonances, which are the result of collective oscillations of surface electrons at a metal-dielectric interface, are able to confine incident light to a deep-subwavelength, or less than λ/10, scale. However, since plasmonic nanomaterials often consist solely of metals, the rapid electron motion in the particle can result in large Ohmic losses, which results in sometimes undesirable heating effects, large spectral linewidths, and short surface plasmon polariton propagation lengths. In comparison, dielectric materials like Si have much lower losses and can sustain narrow linewidths and long propagation distances, but because of their low free carrier concentration, they are not generally able to confine light on the same sub-wavelength scale as metallic plasmonic materials. If these two classes of materials were combined into a single nanostructure, such that the electric field generated by the plasmon resonance were confined into a dielectric core, it would be possible to achieve simultaneous sub-wavelength confinement and low loss. We were able to synthesize such a structure-an epitaxial Si nanowire (NW) core coated with a shell of Au- via a combination of vapor-liquid-solid (VLS) NW growth and metal sputtering. Examining these hybrid NWs using both optical simulations and experimental extinction measurements, we found that they support Mie resonances with quality factors (Q-factors) enhanced up to ~30 times compared to pure dielectric structures and plasmon resonances with optical confinement enhanced up to ~5 times compared to pure metallic structures. We also show that the spectral response of the Mie and plasmon resonances can be reproduced with temporal coupled mode theory (TCMT) and the Fano lineshapes can be attributed to the combination of the high Q-factor resonances, Mie-plasmon coupling, and phase delay of the background optical field. Our work demonstrates a bottom-up method for synthesizing free-standing, cylindrically symmetric, core-shell nanowires that efficiently trap light on a deep sub-wavelength scale, which has implications for many applications in photonics and optoelectronics.As alluded to above, Si NWs have attracted significant attention recently due to their photonic properties, such as their ability to support axially guided optical modes. By periodically modulating dopant gas flow during VLS growth and then wet-chemical etching the as-grown NWs, we can create semi-infinite geometric superlattices, or GSLs. Under specific geometric parameters, Si NW GSLs can support BICs of different orders, which have theoretically infinite lifetimes and Q-factors, and are perfectly isolated from surrounding radiation. If one purposefully detunes those idealized geometric parameters, a quasi-BIC (qBIC) is formed. qBICs retain the high Q-factor and lifetimes of true BICs, but are able to couple with external radiation and manifest as absorption and scattering features. This allows for the identification of trends in different qBICs and their behavior with respect to other Si NW resonances, such as Mie resonances or other qBICs and BICs. We simulated and synthesized a suite of NW GSL geometries that support several qBICs in the visible through NIR spectral regions. Through analysis of the simulated electric and magnetic field profiles, we have also developed a labeling scheme to identify and track different modes across different parameters. We then experimentally detected these qBICs with two, home-built, single-nanowire spectroscopy apparatuses: one measuring extinction and the other measuring photothermal absorption. Our work demonstrates the ability to precisely control the presence, position, and properties of qBICs in Si NW GSLs, with the potential to enhance the ability of photovoltaic Si NWs to harvest the solar spectrum.
546 $a English
590 $a School code: 0153
650 4 $a Chemistry. $3 516420
650 4 $a Nanoscience. $3 587832
650 4 $a Materials science. $3 543314
650 4 $a Physical chemistry. $3 1981412
650 4 $a Analytical chemistry. $3 3168300
653 $a Chemical vapor deposition
653 $a Nanophotonics
653 $a Nanowires
653 $a Plasmonics
653 $a Spectroscopy
690 $a 0485
690 $a 0794
690 $a 0565
690 $a 0486
690 $a 0494
710 2 $a The University of North Carolina at Chapel Hill. $b Chemistry. $e degree granting institution. $3 3820817
720 1 $a Cahoon, James F. $e degree supervisor.
773 0 $t Dissertations Abstracts International $g 85-11B.
790 $a 0153
791 $a Ph.D.
792 $a 2024
856 4 0 $u https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30990182