Photoluminescence enhancement of silicon nanocrystals placed in the near field of a silicon nanowire

Kallel, Houssem; Arbouet, Arnaud; Carrada, Marzia; Assayag, Gérard; Chehaidar, A.; Periwal, P.; Baron, T.; Normand, P.; Paillard, Vincent

doi:10.1103/physrevb.88.081302

Cited by 19 publications

(27 citation statements)

References 29 publications

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“…More generally, the present results provide principle design strategies to achieve uniform, spatially extended and intense near-fields via weak interparticle coupling of plasmonic nanostructures. Thus, these systems are not only suitable for molecular detection and analytics as demonstrated here, but also for other related near-field techniques such as fluorescence1 or tip-enhanced Raman spectroscopy (TERS) imaging29.…”

Section: Discussionmentioning

confidence: 99%

“…Currently, optical detection of few and down to the single molecule level is possible using different conceptual techniques such as fluorescence1, photoluminescence2 or surface-enhanced Raman scattering (SERS)345678910. Noteworthy, all of these methods rely on a common ground: the enhanced near-fields of plasmonic nature encountered in metallic nanostructured substrates, effectively acting as robust signal amplifiers12345678910. Thus, the finest design of generic plasmonic nanostructures for the optical detection of molecules in very low concentrations requires the ability to generate simultaneously an intense, homogeneous and reproducible near-field enhancement379.…”

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confidence: 99%

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Hot-Volumes as Uniform and Reproducible SERS-Detection Enhancers in Weakly-Coupled Metallic Nanohelices

Caridad

Winters

McCloskey

et al. 2017

Sci Rep

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Reproducible and enhanced optical detection of molecules in low concentrations demands simultaneously intense and homogeneous electric fields acting as robust signal amplifiers. To generate such sophisticated optical near-fields, different plasmonic nanostructures were investigated in recent years. These, however, exhibit either high enhancement factor (EF) or spatial homogeneity but not both. Small interparticle gaps or sharp nanostructures show enormous EFs but no near-field homogeneity. Meanwhile, approaches using rounded and separated monomers create uniform near-fields with moderate EFs. Here, guided by numerical simulations, we show how arrays of weakly-coupled Ag nanohelices achieve both homogeneous and strong near-field enhancements, reaching even the limit forreproducible detection of individual molecules. The unique near-field distribution of a single nanohelix consists of broad hot-spots, merging with those from neighbouring nanohelices in specific array configurations and generating a wide and uniform detection zone (“hot-volume”). We experimentally assessed these nanostructures via surface-enhanced Raman spectroscopy, obtaining a corresponding EF of ~107 and a relative standard deviation <10%. These values demonstrate arrays of nanohelices as state-of-the-art substrates for reproducible optical detection as well as compelling nanostructures for related fields such as near-field imaging.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Hot-Volumes as Uniform and Reproducible SERS-Detection Enhancers in Weakly-Coupled Metallic Nanohelices

Caridad

Winters

McCloskey

et al. 2017

Sci Rep

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“…The ′ ( ′ ′ ) ′ ̅ spectrum (panel C) shows a significant drop in the intensity with respect to the ′ ( ′ ′) ′ ̅ spectrum (panel B): this cannot be justified quantitatively just by Raman selection rules, but can be explained by considering the effect of the dielectric mismatch. 55 A NW is a micrometric sized antenna, 56 therefore the absorption 57 and scattering efficiency 58,59,60 are very sensitive to light polarization, and usually result detrimental for light polarized across the longitudinal NW axis 58,59,60 (see also Figure 4 and discussion). It is worth noticing that the experimental spectra were collected exciting the system with the 633 nm line of a HeNe laser, as discussed in the Methods.…”

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confidence: 99%

Crystalline, Phononic, and Electronic Properties of Heterostructured Polytypic Ge Nanowires by Raman Spectroscopy

et al. 2018

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Semiconducting nanowires (NWs) offer the unprecedented opportunity to host different crystal phases in a nanostructure, which enables the formation of polytypic heterostructures where the material composition is unchanged. This characteristic boosts the potential of polytypic heterostructured NWs for optoelectronic and phononic applications. In this work, we investigate cubic Ge NWs where small (∼20 nm) hexagonal domains are formed due to a strain-induced phase transformation. By combining a nondestructive optical technique (Raman spectroscopy) with density-functional theory (DFT) calculations, we assess the phonon properties of hexagonal Ge, determine the crystal phase variations along the NW axis, and, quite remarkably, reconstruct the relative orientation of the two polytypes. Moreover, we provide information on the electronic band alignment of the heterostructure at points of the Brillouin zone different from the one (Γ) where the direct band gap recombination in hexagonal Ge takes place. We demonstrate the versatility of Raman spectroscopy and show that it can be used to determine the main crystalline, phononic, and electronic properties of the most challenging type of heterostructure (a polytypic, nanoscale heterostructure with constant material composition). The general procedure that we establish can be applied to several types of heterostructures.

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“…5,6 Conventional geometries include spherical nanoparticles 4 or nanowires (NWs), 7,8 but also more complex dielectric nanostructures 9 . Dielectric optical antennas are promising candidates for applications in fieldenhanced spectroscopy, [10][11][12][13] imaging, 14 to enhance and control nonlinear effects [15][16][17] or to increase the efficiency in photovoltaics 18 .…”

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Strongly Directional Scattering from Dielectric Nanowires

et al. 2017

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It has been experimentally demonstrated only recently that a simultaneous excitation of interfering electric and magnetic resonances can lead to uni-directional scattering of visible light in zerodimensional dielectric nanoparticles. We show both theoretically and experimentally, that strongly anisotropic scattering also occurs in individual dielectric nanowires. The effect occurs even under either pure transverse electric or pure transverse magnetic polarized normal illumination. This allows for instance to toggle the scattering direction by a simple rotation of the incident polarization. Finally, we demonstrate that directional scattering is not limited to cylindrical cross-sections, but can be further tailored by varying the shape of the nanowires.The search for ways to control light at subwavelength dimensions has increasingly attracted the interest of researchers for about the last two decades. Due to their strong polarizability and tunable plasmon resonances, metallic nanostructures are particularly suitable for the nanoscale manipulation of light -especially at visible frequencies. 1 However, such plasmonic structures suffer from certain drawbacks like strong dissipation associated to the large imaginary part of the dielectric function in metals.Recently, dielectric nanostructures from high-index materials have proven to offer a promising alternative platform with far lower losses. 2 Like in plasmonics, it is possible to tune optical resonances from the near ultraviolet to the near infrared, yet with almost no dissipative losses. At these resonances, which can be of both electric or magnetic nature, strong local field enhancements 3 and intense scattering 4 occur, tunable via the material and the geometry of the nanostructure. Prominent dielectric materials are, among others, silicon, germanium or III-V compound semiconductors with indirect band-gap. 5,6 Conventional geometries include spherical nanoparticles 4 or nanowires (NWs), 7,8 but also more complex dielectric nanostructures 9 . Dielectric optical antennas are promising candidates for applications in fieldenhanced spectroscopy, 10-13 imaging, 14 to enhance and control nonlinear effects [15][16][17] or to increase the efficiency in photovoltaics 18 .A peculiarity of dielectric particles is the possibility to simultaneously obtain a strong electric and magnetic response using very simple geometries. 3,4,19,20 Recently, it has been independently shown by two research groups, 21,22 that exclusive forward (FW) or backward (BW) scattering, predicted by Kerker et al. in 1983 for hypothetical magneto-dielectric particles, 23 can be real- * ized in the visible spectral range using dielectric nanoparticles. Kerker et al. described two possible configurations, called the Kerker conditions. At the first Kerker condition zero backward scattering occurs for equal electric permittivity and magnetic permeability ( r = µ r ). The second Kerker condition predicts zero forward scattering in small spherical particles when the first order magnetic and electric Mie coeff...

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Photoluminescence enhancement of silicon nanocrystals placed in the near field of a silicon nanowire

Cited by 19 publications

References 29 publications

Hot-Volumes as Uniform and Reproducible SERS-Detection Enhancers in Weakly-Coupled Metallic Nanohelices

Hot-Volumes as Uniform and Reproducible SERS-Detection Enhancers in Weakly-Coupled Metallic Nanohelices

Crystalline, Phononic, and Electronic Properties of Heterostructured Polytypic Ge Nanowires by Raman Spectroscopy

Strongly Directional Scattering from Dielectric Nanowires

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