Complex dewetting scenarios of ultrathin silicon films for large-scale nanoarchitectures

Naffouti, Meher; Backofen, Rainer; Salvalaglio, Marco; Bottein, Thomas; Lodari, Mario; Voigt, Axel; David, Thomas; Benkouider, Abdelmalek; Fraj, Ibtissem; Favre, Luc; Ronda, A.; Berbézier, Isabelle; Grosso, David; Abbarchi, Marco; Bollani, Monica

doi:10.1126/sciadv.aao1472

Cited by 91 publications

(102 citation statements)

References 74 publications

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“…One viable and promising route is solid-state dewetting of ultra-thin films of metals 18,[34][35][36][37][38][39][40][41] and semiconductors, [42][43][44][45][46] a natural phenomenon exploited for the self-assembly of high-quality photonic structures. The instability giving rise to the dewetting phenomenon in thin films is mediated by the surface diffusion of atoms and occurs upon annealing at high temperature (even well below the melting point of the material) [47][48][49][50][51][52][53][54][55][56][57][58] .…”

Section: Introductionmentioning

confidence: 99%

Self-assembled antireflection coatings for light trapping based on SiGe random metasurfaces

Bouabdellaoui

Checcucci

Wood

et al. 2018

Phys. Rev. Materials

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We demonstrate a simple self-assembly method based on solid state dewetting of ultra-thin silicon films and germanium deposition for the fabrication of efficient anti reflection coatings on silicon for light trapping. Via solid state dewetting of ultra-thin silicon on insulator and epitaxial deposition of Ge we fabricate SiGe islands with a high surface density, randomly positioned and broadly varied in size. This allows to reduce the reflectance to low values in a broad spectral range (from 500 nm to 2500 nm) and a broad angle (up to 55 degrees) and to trap within the wafer a large portion of the impinging light (∼40%) also below the band-gap, where the Si substrate is non-absorbing. Theoretical simulations agree with the experimental results showing that the efficient light coupling into the substrate mediated by Mie resonances formed within the SiGe islands. This lithography-free method can be implemented on arbitrarily thick or thin SiO2 layers and its duration only depends on the sample thickness and on the annealing temperature.

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Section: Introductionmentioning

confidence: 99%

Self-assembled antireflection coatings for light trapping based on SiGe random metasurfaces

Bouabdellaoui

Checcucci

Wood

et al. 2018

Phys. Rev. Materials

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“…Top panels: dark-field optical microscope (100×magnification, NA=0.75) of monocrystalline Si islands on 25 nm BOX. From the left to the right, panels are illustrated with several islands organization obtained from different initial patch size and shape [31,35]. Bottom panels: same as the top panels for islands transferred in a PDMS slice.…”

Section: Discussionmentioning

confidence: 99%

“…We now take into account the case of templated dewetting of commercial UT-SOI: [31,35] by changing the etched patch size and shape (e.g. simple squares, squares with a central cross, parallel trenches) we obtain different arrangement of the Si particles sitting on a 25nm thick BOX ( figure 6 top panels).…”

Section: Methods B: Transfer In Pdms Slicesmentioning

confidence: 99%

“…The thin Si 1−x Ge x layers are first cleaned with an annealing flash at 600°C for 30′ and then annealed between 620°C and 800°C for 1-4 h in order to induce the dewetting [27][28][29][30]. Templated dewetting is obtained by etching the UT-SOI via e-beam lithography and reactive ion etching (EBL and RIE) prior to annealing [31].…”

Section: Panorama Of Different Dewetting Scenariosmentioning

confidence: 99%

“…A last example is templated dewetting of UT-SOI (figure 1(e)): [27,29,31,34,35] by etching a commercial UT-SOI (figure 1(e), first panel) with patches of well defined size and spacing and eventually adding other features (e.g. pits and holes) the annealing provides ordered arrays of individual islands (figure 1(e), second to fourth panel), complex assemblies of islands [29,34] (figure 1(e), fifth panel) and complex nanoarchitectures [31,35].…”

Section: Panorama Of Different Dewetting Scenariosmentioning

confidence: 99%

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Flexible photonic devices based on dielectric antennas

et al. 2020

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Flexible and stretchable photonics are emerging fields aiming to develop novel applications where the devices need to conform to uneven surfaces or whenever lightness and reduced thickness are major requirements. However, owing to the relatively small refractive index of transparent soft matter including most polymers, these materials are not well adapted for light management at visible and near-infrared frequencies.Here we demonstrate simple, low cost and efficient protocols for fabricating Si 1−x Ge x -based, sub-micrometric dielectric antennas over record scales (50 mm wafers) with ensuing hybrid integration into different plastic supports. The transfer process has a near-unity yield: up to 99.94% for disordered structures and 99.5% for the ordered counterpart. Finally, we benchmark the optical quality of the dielectric antennas with light scattering measurements, demonstrating the control of the islands structural color and the onset of sharp Mie modes after encapsulation in plastic. Thanks to the ease of implementation of our fabrication methods, these results are relevant for the integration of SiGe-based dielectric Mie resonators in flexible substrates over large surfaces.

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Titania‐Based Spherical Mie Resonators Elaborated by High‐Throughput Aerosol Spray: Single Object Investigation

Checcucci

Bottein

Claude

et al. 2018

Adv Funct Materials

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The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10. 1002/adfm.201801958. tives to replace complex and bulky optical elements. This unique ability is due to strong modifications of the local density of optical states occurring in sub-micrometric objects made of materials featuring high dielectric constant and sufficiently small absorption losses.Most studies over the last years have mainly addressed silicon- [4][5][6][7][8][9][10] and germanium-based [11][12][13][14] Mie resonators, demonstrating that they could outperform their metallic counterpart supporting localized plasmonic resonances. However, the large absorption of group IV semiconductor compounds at short wavelengths induces strong optical losses, limiting their potential applicability as efficient devices especially at blue and near-UV frequencies [15,16] (e.g. at 450 nm: n Si = 4.5, k Si = 0.13; n Ge = 4.0, k Ge = 2.24). Furthermore, with a few exception based on colloids [4,17,18] and solid state dewetting, [13,[19][20][21][22][23] typical nanofabrication methods of Si(Ge)-based Mie resonators rely on top-down technologies that are not easy to scale-up at affordable prices.TiO 2 -based optical devices are an interesting alternative to Si, since Titania has a relatively high refractive index and is fully transparent up to UV frequencies [24,25] (e.g.: at 450 nm: n TiO2 = 2.55, k TiO2 = 1.2 × 10 −5 ; at 370 nm: n TiO2 = 2.83, k TiO2 = 1 × 10 −3 ) rendering it, for instance, a strategic material to manipulate the light emitted by conventional GaN-based blue LEDs (at about 450 nm). TiO 2 can be prepared by high-throughput chemical processes, which is a prerequisite for applications requiring large surface systems. It also has many other advantages over Si and metals that are its high chemical, mechanical, and thermal stability, nontoxicity, and relative natural abundance.To date, several groups have studied the properties of Titania particles as dielectric resonators prepared using conventional top-down microfabrication technologies [26][27][28][29][30] or soft-nanoimprint lithography. [31,32] They all confirmed that electromagnetic resonances could be generated within these metal oxide objects. However, the limited exploitation of this material is mainly due to the difficulty in applying conventional top-down fabrication methods to TiO 2 . Additionally, such approaches do not allow the preparation of spherical resonators, [33] which may be interesting for many applications with effective metamaterials, such as beam steering and back-scattering-free optics, [11,[34][35][36][37][38][39][40][41][42][43][44][45]

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Complex dewetting scenarios of ultrathin silicon films for large-scale nanoarchitectures

Abstract: Si-based nanoarchitectures are formed with unprecedented precision and reproducibility via templated dewetting of thin SOI.

Cited by 91 publications

References 74 publications

Self-assembled antireflection coatings for light trapping based on SiGe random metasurfaces

Self-assembled antireflection coatings for light trapping based on SiGe random metasurfaces

Flexible photonic devices based on dielectric antennas

Titania‐Based Spherical Mie Resonators Elaborated by High‐Throughput Aerosol Spray: Single Object Investigation

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