Textile Prototyping Lab - A Platform and Open Laboratory for the Promotion of Open Innovation and Networking between Research, Design and Industry

This paper introduces and discusses the Textile Prototyping Lab (hereinafter referred to as 'TPL'), which is a joint research project in its early stages of five organisations from the fields of textiles, electronic research, design and economics. It comprises the concept, design, installation and testing of a textile prototyping laboratory that is more open, flexible and interdisciplinary than other textile-related laboratories known to date. The core topic of the project is Open Innovation, which means research and development is conducted within the new context of sharing resources and results amongst the directly involved actors and the interested community consisting of industry, individual professionals and students. Thus the research and development activities relevant to the individual parties involved in this project are conducted jointly and made available beyond their own organisational boundaries. The concept is implemented by five partners with a sound expertise in their respective fields of action: The Saxon Textile Research Institute (STFI) and the Textile Research Institute Thuringia-Vogtland (TITV Greiz) - two leading German textile research institutes - are contributing their expertise in textile process chains, lightweight construction and Smart Textiles to the project. The Fraunhofer Institute for Reliability and Microintegration (IZM) supports the lab in the field of microelectronic integration into textile structures, but Fab Lab Berlin - with their expertise related to Open Innovation processes. weißensee academy of art berlin serves as the network coordinator and contributes its knowledge in textile design, design education and design research. This research project is part of futureTEX, an interdisciplinary competence network in which industry, scientific institutions and associations work together to actively shape the future of the German textile industry, fostering new interdisciplinary ideas, funded by the Federal Ministry of Education and Research in Germany. The infrastructure of TPL consists of a digitally supported central prototyping lab located at the weißensee academy of art berlin, supplemented by highly specialised facilities and 'focus labs‘ located at the partner institutes. A specifically developed software connects the different facilities and supports lean development processes. Additionally an extensive material library embodies and represents the textile expertise and serves as an analogue resource of references, information and inspiration in order to communicate the competence fields and technological possibilities of TPL. TPL connects different stakeholders from the textile sector and beyond promoting exchange among these. Diverse actors benefit from the competences of the TPL infrastructure and its network. The processes are adapted to serve different user types (e.g. industry, SMEs, start-ups, designers, engineers, developers, free-lancers, students). Thus TPL is an open and agile place where interdisciplinary practices and interests meet to foster quick and effective innovation processes within the extended field of textiles

Programmable Assembly of Hybrid Nanoclusters

Hybrid nanoparticle clusters (often metallic) are interesting plasmonic materials with tunable resonances and a near-field electromagnetic enhancement at interparticle junctions. Therefore, in recent years, we have witnessed a surge in both the interest in these materials and the efforts to obtain them. However, a versatile fabrication of hybrid nanoclusters, that is, combining more than one material, still remains an open challenge. Current lithographical or self-assembly methods are limited to the preparation of hybrid clusters with up to two different materials and typically to the fabrication of hybrid dimers. Here, we provide a novel strategy to deposit and align not only hybrid dimers but also hybrid nanoclusters possessing more complex shapes and compositions. Our strategy is based on the downscaling of sequential capillarity-assisted particle assembly over topographical templates. As a proof of concept, we demonstrate dimers, linear trimers, and 2D nanoclusters with programmable compositions from a range of metallic nanoparticles. Our process does not rely on any specific chemistry and can be extended to a large variety of particles and shapes. The template also simultaneously aligns the hybrid (often anisotropic) nanoclusters, which could facilitate device integration, for example, for optical readout after transfer to other substrates by a printing step. We envisage that this new fabrication route will enable the assembly and positioning of complex hybrid nanoclusters of different functional nanoparticles to study coupling effects not only locally but also at larger scales for new nanoscale optical devices

Cascaded Assembly of Complex Multiparticle Patterns

A method for the cascaded capillary assembly of different particle populations in a single assembly cycle is presented. The method addresses the increasing need for fast and simple fabrication of multicomponent arrays from colloidal micro- and nanoscale building blocks for constructing nanoelectronic, optical, and sensing devices. It is based on the use of a microfluidic device from which two independent capillary bridges extend. The menisci of the capillary bridges are pulled over a template with trapping sites that receive the colloidal particles. We describe the parameters for simultaneous, high-yield assembly from both menisci and demonstrate the applicability of the process by means of the size-selective assembly of particles of different diameters and also by the fabrication of two-component particle clusters with defined shape and composition. This approach allows the fabrication of multifunctional particle clusters having different functionalities at predetermined positions

Accurate Location and Manipulation of Nanoscaled Objects Buried under Spin-Coated Films

Detection and precise localization of nanoscale structures buried beneath spin-coated films are highly valuable additions to nanofabrication technology. In principle, the topography of the final film contains information about the location of the buried features. However, it is generally believed that the relation is masked by flow effects, which lead to an upstream shift of the dry film’s topography and render precise localization impossible. Here we demonstrate, theoretically and experimentally, that the flow-shift paradigm does not apply at the submicrometer scale. Specifically, we show that the resist topography is accurately obtained from a convolution operation with a symmetric Gaussian kernel whose parameters solely depend on the resist characteristics. We exploit this finding for a 3 nm precise overlay fabrication of metal contacts to an InAs nanowire with a diameter of 27 nm using thermal scanning probe lithography

Testing the Equivalence between Spatial Averaging and Temporal Averaging in Highly Dilute Solutions

Diffusion relates the flux of particles to the local gradient of the particle density in a deterministic way. The question arises as to what happens when the particle density is so low that the local gradient becomes an ill-defined concept. The dilemma was resolved early last century by analyzing the average motion of particles subject to random forces whose magnitude is such that the particles are always in thermal equilibrium with their environment. The diffusion dynamics is now described in terms of the probability density of finding a particle at some position and time and the probabilistic flux density, which is proportional to the gradient of the probability density. In a time average sense, the system thus behaves exactly like the ensemble average. Here, we report on an experimental method and test this fundamental equivalence principle in statistical physics. In the experiment, we study the flux distribution of 20 nm radius polystyrene particles impinging on a circular sink of micrometer dimensions. The particle concentration in the water suspension is approximately 1 particle in a volume element of the dimension of the sink. We demonstrate that the measured flux density is exactly described by the solution of the diffusion equation of an infinite system, and the flux statistics obeys a Poissonian distribution as expected for a Markov process governing the random walk of noninteracting particles. We also rigorously show that a finite system behaves like an infinite system for very long times despite the fact that a finite system converges to a zero flux empty state

Enhanced Second-Harmonic Generation from Sequential Capillarity-Assisted Particle Assembly of Hybrid Nanodimers

We show enhanced second-harmonic generation (SHG) from a hybrid metal–dielectric nanodimer consisting of an inorganic perovskite nanoparticle of barium titanate (BaTiO₃) coupled to a metallic gold (Au) nanoparticle. BaTiO₃–Au nanodimers of 100 nm/80 nm sizes are fabricated by sequential capillarity-assisted particle assembly. The BaTiO₃ nanoparticle has a noncentrosymmetric crystalline structure and generates bulk SHG. We use the localized surface plasmon resonance of the gold nanoparticle to enhance the SHG from the BaTiO₃ nanoparticle. We experimentally measure the nonlinear signal from assembled nanodimers and demonstrate an up to 15-fold enhancement compared to a single BaTiO₃ nanoparticle. We further perform numerical simulations of the linear and SHG spectra of the BaTiO₃–Au nanodimer and show that the gold nanoparticle acts as a nanoantenna at the SHG wavelength

Understanding How Charged Nanoparticles Electrostatically Assemble and Distribute in 1‑D

The effects of increasing the driving forces for a 1-D assembly of nanoparticles onto a surface are investigated with experimental results and models. Modifications, which take into account not only the particle–particle interactions but also particle–surface interactions, to previously established extended random sequential adsorption simulations are tested and verified. Both data and model are compared against the heterogeneous random sequential adsorption simulations, and finally, a connection between the two models is suggested. The experiments and models show that increasing the particle–surface interaction leads to narrower particle distribution; this narrowing is attributed to the surface interactions compensating against the particle–particle interactions. The long-term advantage of this work is that the assembly of nanoparticles in solution is now understood as controlled not only by particle–particle interactions but also by particle–surface interactions. Both particle–particle and particle–surface interactions can be used to tune how nanoparticles distribute themselves on a surface

Sub-10 Nanometer Feature Size in Silicon Using Thermal Scanning Probe Lithography

High-resolution lithography often involves thin resist layers which pose a challenge for pattern characterization. Direct evidence that the pattern was well-defined and can be used for device fabrication is provided if a successful pattern transfer is demonstrated. In the case of thermal scanning probe lithography (t-SPL), highest resolutions are achieved for shallow patterns. In this work, we study the transfer reliability and the achievable resolution as a function of applied temperature and force. Pattern transfer was reliable if a pattern depth of more than 3 nm was reached and the walls between the patterned lines were slightly elevated. Using this geometry as a benchmark, we studied the formation of 10–20 nm half-pitch dense lines as a function of the applied force and temperature. We found that the best pattern geometry is obtained at a heater temperature of ∼600 °C, which is below or close to the transition from mechanical indentation to thermal evaporation. At this temperature, there still is considerable plastic deformation of the resist, which leads to a reduction of the pattern depth at tight pitch and therefore limits the achievable resolution. By optimizing patterning conditions, we achieved 11 nm half-pitch dense lines in the HM8006 transfer layer and 14 nm half-pitch dense lines and L-lines in silicon. For the 14 nm half-pitch lines in silicon, we measured a line edge roughness of 2.6 nm (3σ) and a feature size of the patterned walls of 7 nm