Optical properties and oxidation of<i>α</i>-phase Ag–Al thin films

Silva, Kaludewa S. B. de; Keast, V. J.; Gentle, Angus; Cortie, Michael B.

doi:10.1088/1361-6528/aa5782

Cited by 20 publications

(19 citation statements)

References 49 publications

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“…This suggests an improvement in the excitation efficiency of LSPR in the ultraviolet region, defined, in the case of spherical particles, as the ratio -QLSPR = -ε'/ε". In the case of indium rich layers, a switch of the ε' sign is observed due to the presence of an interband transition of indium at 1.4 -2.8 eV [9,10]. These coatings exhibit higher ε" values in the range of 2 -5 eV; thus, they have lower QLSPR values in this spectral region.…”

Section: Resultsmentioning

confidence: 99%

“…An adjustment of the plasmon resonance can be achieved by using bimetallic alloys of the two metals [9]. Special attention to the plasmonic activity of silver-rich Ag-In alloys (with indium content up to 12 at %) was paid in earlier works, while the Ag-In alloys with a higher indium content based on mixture of intermetallic compounds and the In-rich materials have remained less studied.…”

Section: Introductionmentioning

confidence: 99%

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Optical properties of nanostructured bimetallic films from the Ag-In and Ag-Sb systems and their surface-enhanced fluorescence application

Katrova

Hristova-Vasileva

Atanasova

et al. 2022

J. Phys.: Conf. Ser.

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The possibility for tuned excitation of surface plasmon resonance in Ag-In and Ag-Sb films with different compositions and thicknesses was studied in terms of preparation and microstructural and optical properties. The analyses show that plasmon excitation can be achieved both by changing the thickness of the deposited bimetallic films and by varying their composition. The imaginary ε'' part of the complex permittivity of the thin films has a maximum due to the transverse oscillations of free electrons in the range of 1 eV to 3.5 eV. The films’ applicability as amplifying substrates in surface-enhanced fluorescence was tested. Tryptophan and Cu (II)-phthalocyanine (CuPc) dye were used to analyze the efficiency of the localized surface plasmon resonance excitation in the ultraviolet spectral region. Amplification enhancing coefficient of 4.17 times was obtained in the case of CuPc dye.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optical properties of nanostructured bimetallic films from the Ag-In and Ag-Sb systems and their surface-enhanced fluorescence application

Katrova

Hristova-Vasileva

Atanasova

et al. 2022

J. Phys.: Conf. Ser.

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Section: Optical Properties Of Metal Alloysmentioning

confidence: 99%

“…Thus, several research groups, including ours, have recently merged two almost orthogonal fields, photonics, and metallurgy, to pursue metallic materials with arbitrary permittivity. [ 1–5 ] Alloying is now a burgeoning framework for achieving materials with engineered optical properties, encompassing both nanostructures and thin films, as will be surveyed in this Review.…”

Section: Introductionmentioning

confidence: 99%

Emergent Opportunities with Metallic Alloys: From Material Design to Optical Devices

Gong

Lyu

Palm

et al. 2020

Advanced Optical Materials

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devices is the fact that their dielectric function (i.e., permittivity, ε = ε 1 + iε 2) is predefined. Thus, several research groups, including ours, have recently merged two almost orthogonal fields, photo nics, and metallurgy, to pursue metallic materials with arbitrary permit tivity. [1-5] Alloying is now a burgeoning framework for achieving materials with engineered optical properties, encom passing both nanostructures and thin films, as will be surveyed in this Review. Plasmonics exploits the interaction of incident electromagnetic fields with the col lective motion of free electrons (plasmons) in metals. This phenomenon confines the electromagnetic fields in close vicinity of the metal interfaces, dramatically enhancing the electrical field intensity surrounding the material. [6-8] Plasmons can be divided into two categories: surface plasmon polaritons (SPP) that propagate along the metal and dielectric interface, and localized surface plasmon resonance (LSPR) that are confined in a subwavelength nanostructure. For the latter, their optical scattering or absorp tion (and/or the nearby dielectrics and semiconductors) can be significantly increased. As a result, these enhancement effects are the underpinnings to a range of novel optical processes, and have found countless applications in photovoltaics, [9-11] photo catalysis, [12-14] bio and chemicalsensing, [15,16] electrooptical modu lation, [17,18] and superabsorbers. [19-21] As expected, the features of either type of plasmon are strongly dependent upon the dielectric function of the material, which is somewhat fixed in metals. Concerning materials, coinage metals, such as Au, Ag, or Cu, are widely used in photonics due to their abundant free electrons and chemical stability. [1] Other noble metals including Metallic nanostructures and thin films are fundamental building blocks for next-generation nanophotonics. Yet, the fixed permittivity of pure metals often imposes limitations on the materials employed and/or on device performance. Alternatively, metallic mixtures, or alloys, represent a promising pathway to tailor the optical and electrical properties of devices, enabling further control of the electromagnetic spectrum. In this Review, a survey of recent advances in photonics and plasmonics achieved using metal alloys is presented. An overview of the primary fabrication methods to obtain subwavelength alloyed nanostructures is provided, followed by an in-depth analysis of experimental and theoretical studies of their optical properties, including their correlation with band structure. The broad landscape of optical devices that can benefit from metallic materials with engineered permittivity is also discussed, spanning from superabsorbers and hydrogen sensors to photovoltaics and hot electron devices. This Review concludes with an outlook of potential research directions that would benefit from the on demand optical properties of metallic mixtures, leading to new optoelectronic materials and device opportunities.

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“…Compared to the commonly available polycrystalline films [ 20 ] obtained by conventional techniques, high‐quality single crystalline Al films [ 21–25 ] can be achieved by molecular beam epitaxy (MBE) and enhanced performances such as low losses have been confirmed. In terms of reducing the optical loss, people have tried alloys and intermetallic compounds, such as Au–Cd, Au–Ni, Au–Cu, Au–Al, Ag–Al, Cu–Al, PtAl 2 , and AuAl 2 , [ 26–29 ] to modify the electron density of states and band structures so that the dielectric functions are modified. However, alloys are often grown by sputtering and it is difficult to obtain single crystalline films so the defects related issues still limit their properties.…”

Section: Figurementioning

confidence: 99%

Interface Engineering and Epitaxial Growth of Single‐Crystalline Aluminum Films on Semiconductors

Zhang

Xia

et al. 2020

Adv Materials Inter

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Single crystalline aluminum (Al) films are grown on GaAs substrates by molecular beam epitaxy. The high crystalline quality and sharp interfaces of the epitaxial Al films are confirmed by high‐resolution X‐ray diffraction and transmission electron microscopy. Semi‐metallic ErAs is inserted to the Al/GaAs interface to modify the band structure and reduce the optical loss of Al without degrading the crystalline quality. The optical dielectric properties of the Al films are measured by spectroscopic ellipsometry and the optical loss (ε2) is reduced in a broad spectral region from ultraviolet (UV) to near‐infrared compared to the widely quoted Palik's values. In particular, the loss in the visible region is reduced by a factor of three, indicating the effective energy band engineering by ErAs.

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Optical properties and oxidation ofα-phase Ag–Al thin films

Cited by 20 publications

References 49 publications

Optical properties of nanostructured bimetallic films from the Ag-In and Ag-Sb systems and their surface-enhanced fluorescence application

Optical properties of nanostructured bimetallic films from the Ag-In and Ag-Sb systems and their surface-enhanced fluorescence application

Emergent Opportunities with Metallic Alloys: From Material Design to Optical Devices

Interface Engineering and Epitaxial Growth of Single‐Crystalline Aluminum Films on Semiconductors

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