Gallium Polymorphs: Phase‐Dependent Plasmonics

Gutiérrez, Yael; Losurdo, María; García‐Fernández, Pablo; Maza, Marta Sainz de la; González, Francisco; Brown, April S.; Everitt, Henry O.; Junquera, Javier; Moreno, Fernando

doi:10.1002/adom.201900307

Cited by 26 publications

(37 citation statements)

References 49 publications

(79 reference statements)

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“…The high-energy mode (TO mode) also shows a near-field enhancement distribution concentrated at the NP-substrate interface for the spherical case ( = 180˚), due to its coupling with the cavity. As decreases, the mode gets concentrated at the nanoparticle surface, which is consistent with its TO-mode character [26].…”

Section: Effect Of Nanoparticle Shape: Contact Angle Between Ga Nps Asupporting

confidence: 73%

Understanding Electromagnetic Interactions and Electron Transfer in Ga Nanoparticle–Graphene–Metal Substrate Sandwich Systems

et al. 2019

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Plasmonic metal nanoparticle (NP)–graphene (G) systems are of great interest due their potential role in applications as surface-enhanced spectroscopies, enhanced photodetection, and photocatalysis. Most of these studies have been performed using noble metal NPs of silver and gold. However, recent studies have demonstrated that the noble metal–graphene interaction leads to strong distortions of the graphene sheet. In order to overcome this issue, we propose the use of Ga NPs that, due to their weak interaction with graphene, do not produce any deformation of the graphene layers. Here, we analyze systems consisting of Ga NP/G/metal sandwich coupling structures, with the metal substrate being, specifically, copper (Cu) and nickel (Ni), i.e., Ga NP/G/Cu and Ga NPs/G/Ni. We experimentally show through real-time plasmonic spectroscopic ellipsometry and Raman spectroscopy measurements of the quenching of the Ga NP localized surface plasmon resonance (LSPR) depending on the wetting of the graphene by the Ga NPs and on the electron transfer through graphene. Theoretical finite-difference time-domain (FDTD) simulations supportively demonstrate that the LSPR in such sandwich structures strongly depends on the contact angle of the NP with graphene. Finally, we also provide evidence of the electron transfer from the Ga NPs into the graphene and into the metal substrate according to the work function alignments. These considerations about the contact angle and, consequently, geometry and wetting of the metal NPs on graphene, are useful to guide the design of those plasmonic systems to maximize electromagnetic enhancement.

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Section: Effect Of Nanoparticle Shape: Contact Angle Between Ga Nps Asupporting

confidence: 73%

Understanding Electromagnetic Interactions and Electron Transfer in Ga Nanoparticle–Graphene–Metal Substrate Sandwich Systems

et al. 2019

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“…Ref. [19] ma previous stud Furthermore, nanoparticles, being γ lv the l (of the order o transitions below that energy, l- [18], γ-, and δ-Ga have Drude-like metallic behavior [19] at atmospheric pressure. Indeed, pressure is another parameter that may be exploited in active and phase-change plasmonics.…”

Section: Introductionmentioning

confidence: 54%

Dielectric function and plasmonic behavior of Ga(II) and Ga(III)

Gutiérrez

Losurdo

García‐Fernández

et al. 2019

Opt. Mater. Express

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In order to exploit gallium's (Ga) rich polymorphism in the design of phase-change plasmonic systems, accurate understanding of the dielectric function of the different Ga-phases is crucial. The dielectric dispersion profiles of those phases appearing at atmospheric pressure have been reported in the literature, but there is no information on the dielectric function of the high-pressure Ga-phases. Through first principles calculations we present a comprehensive analysis of the interdependence of the crystal structure, band structure, and dielectric function of two high-pressure Ga phases (Ga(II) and Ga(III)). The plasmonic behavior of these high-pressure Ga-phases is compared to those stable (liquid-and α-Ga) and metastable (β-, γ-and δ-Ga) at atmospherics pressure. This analysis can have important implications in the design of pressuredriven phase-change Ga plasmonic devices and high-pressure SERS substrates.

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“…In a similar way, strong interband transitions were proposed to be an important cause of the negative ε 1 values in the visible for a broader gamut of alternative plasmonic materials from the p block of periodic table: Sb and Ga in its solid α phase and Te, Bi, Sb and their binary and ternary chalcogenides . Materials with interband‐induced plasmonic properties can also be found outside of the p block.…”

Section: Plasmon Resonancesmentioning

confidence: 90%

Spectrally Tailored Light‐Matter Interaction in Lithography‐Free Functional Nanomaterials

Toudert

2019

Physica Status Solidi (a)

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Functional materials with a tailored optical response are needed for applications including coloring, optical instrumentation, data encryption, thermal radiation shaping, energy harvesting, and environmental or biological sensing. A given application requires the material to absorb, transmit, reflect, or scatter light in a suitable way, in a specific, narrow, or broad spectral range selected in the visible or infrared. To achieve the optical response and functionality needed, it is appealing to design nanomaterials with a suitable composition and a properly engineered structure, and this should ideally be realized with high‐throughput and cost‐effective fabrication methods. Herein, the aim is to provide a view on some very recently reported functional nanomaterials showing an optical response tailored for applications by lithography‐free methods. It is illustrated how assembling tailor‐made nanostructures based on the expanding library of optical materials (and their specific wavelength‐dependent dielectric functions) enables harnessing a variety of optical resonances (plasmonic, epsilon near zero, high refractive index Mie, film interference) to tailor the nanomaterials' optical response. It is also shown that building the nanostructures from novel optical materials brings special functionalities, such as a switchable response. Examples of applications are put forward.

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Gallium Polymorphs: Phase‐Dependent Plasmonics

Cited by 26 publications

References 49 publications

Understanding Electromagnetic Interactions and Electron Transfer in Ga Nanoparticle–Graphene–Metal Substrate Sandwich Systems

Understanding Electromagnetic Interactions and Electron Transfer in Ga Nanoparticle–Graphene–Metal Substrate Sandwich Systems

Dielectric function and plasmonic behavior of Ga(II) and Ga(III)

Spectrally Tailored Light‐Matter Interaction in Lithography‐Free Functional Nanomaterials

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