lithography, provide great flexibility but are slow and expensive, and are therefore not feasible. Conventional scalable techniques, for instance random etching processes such as chemical wet etching [3,4] or plasma dry etching, [5,6] operate in a small window of parameters, thus offering only limited freedom of design and the statistics of fabricated disordered interfaces is more or less fixed. Bottom up, self-organized colloid deposition is a promising candidate for scalable interface texturing. [7][8][9] There are a number of both theoretical and experimental studies on how structures fabricated by colloid deposition can be used for light management in photo nic devices such as solar cells. [10][11][12][13][14][15] Colloid-defined samples are mostly used to produce strictly periodic structures, such as hexagonal photonic crystals and nanoparticle arrays. [7][8][9] However, partly ordered and disordered structures have been shown to possibly perform significantly better than perfectly ordered structures in recent studies. [15][16][17][18][19][20] Nevertheless, a colloid-based deposition technique to prepare disordered structures with the ability to tailor its topographical statistics, and thus a tailored optical response, is still missing.In this work, we investigate the scalable deposition of disordered arrangements of colloidal nanoparticles that selforganize on a substrate to create disordered topographies of defined statistics. The fabricated substrates may serve as templates in a subsequent fabrication process, e.g., etching, nanosphere lithography, or overcoating with optical materials such as absorber layers for solar cells or light generation layers for solid-state lighting. Irregular deposition of colloids is often governed by unwanted effects, such as ordering into regular periodic patterns, autostratification, or separation of particle sizes due to surface tension or depletion forces. [9,[21][22][23][24] Here, we introduce a self-stabilized particle deposition process to overcome these effects. The process allows us to control lateral and vertical structure dimensions by setting size distribution and interparticle spacing of a sub-monolayer of particles through experimentally easy-to-access parameters. By understanding the deposition process and the resulting statistics, we can predict the topography and thereby enable optimization of these structures for a specific application without the need for laborious trial-and-error experiments.The pattern structure of the substrates fabricated by our procedure is of correlated disorder and reveals features that resemble hyperuniformity. [25,26] Like glasses, disorderd Disordered optical substrates play a key role in photonic applications. Furthermore, structures of correlated, in particular hyperuniform, disorder are an emerging new class of photonic material enabling new ways of k-space engineering. Yet, there are little to no feasible technologies that allow fabrication of tailored disordered structures to facilitate a tailored optical response. This work ...

Arrays of nanoparticles exploited in light scattering applications commonly only feature either a periodic or a rather random arrangement of its constituents. For the periodic case, light scattering is mostly governed by the strong spatial correlations of the arrangement, expressed by the structure factor. For the random case, structural correlations cancel each other out and light scattering is mostly governed by the scattering properties of the individual scatterer, expressed by the form factor. In contrast to these extreme cases, it is shown here that hyperuniform disorder in self‐organized large‐area arrays of high refractive index nanodisks enables both structure and form factor to impact the resulting scattering pattern, offering novel means to tailor light scattering. The scattering response from the authors’ nearly hyperuniform interfaces can be exploited in a large variety of applications and constitutes a novel class of advanced optical materials.

A large variety of different strategies has been proposed as alternatives to random textures to improve light coupling into solar cells. While the understanding of dedicated nanophotonic systems deepens continuously, only a few of the proposed designs are industrially accepted due to a lack of scalability. In this Article, a tailored disordered arrangement of high-index dielectric submicron-sized titanium dioxide (TiO2) disks is experimentally exploited as an antireflective Huygens’ metasurface for standard heterojunction silicon solar cells. The disordered array is fabricated using a scalable bottom-up technique based on colloidal self-assembly that is applicable virtually irrespective of material or surface morphology of the device. We observe a broadband reduction of reflectance resulting in a relative improvement of a short-circuit current by 5.1% compared to a reference cell with an optimized flat antireflective indium tin oxide (ITO) layer. A theoretical model based on Born’s first approximation is proposed that links the current increase in the arrangement of disks expressed in terms of the structure factor S(q) of the disk array. Additionally, we discuss the optical performance of the metasurface within the framework of helicity preservation, which can be achieved at specific wavelengths for an isolated disk for illumination along the symmetry axis by tuning its dimensions. By comparison to a simulated periodic metasurface, we show that this framework is applicable in the case of the structure factor approaching zero and the disks’ arrangement becoming stealthy hyperuniform.

Reactive atmospheric plasma jets containing halogenous compounds are employed as locally acting tools for surface figure shaping or surface modification in ultra‐precision surface machining technologies. In the current study, the interaction between an atmospheric CCl4/O2 containing plasma jet with silicon surface is investigated aiming at elucidating the chemical kinetics of surface reactions. Different process regimes are identified comprising material removal as well as polymeric and oxide layer formation, which depend on the ratio of the reactive components and substrate surface temperature. XPS and SEM measurements support the findings.

Abstract:We study the light-trapping properties of surface textures generated by a bottomup approach, which utilizes monolayers of densely deposited nanospheres as a template. We demonstrate that just allowing placement disorder in monolayers from identical nanospheres can already lead to a significant boost in light-trapping capabilities. Further absorption enhancement can be obtained by involving an additional nanosphere size species. We show that the Power Spectral Density provides limited correspondence to the diffraction pattern and in turn to the short-circuit current density enhancement for large texture modulations. However, in predicting the optimal nanosphere size distribution, we demonstrate that full-wave simulations of just a c-Si semi-infinite halfspace at a single wavelength in the range where light trapping is of main importance is sufficient to provide an excellent estimate. The envisioned bottom-up approach can thus reliably provide good light-trapping surface textures even with simple nanosphere monolayer templates defined by a limited number of control parameters: two nanosphere radii and their occurrence probability.