Three-dimensional Lithography Research Articles

Three-dimensional direct lithography of stable quantum dots in hybrid glass

Abstract Semiconductor quantum dots (QDs), as high-performance materials, play an essential role in contemporary industry, mainly due to their high photoluminescent quantum yield, wide absorption characteristics, and size-dependent light emission. It’s essential to construct well-defined micro-/nano- structures using QDs as building blocks for micro-optics applications. However, the fabrication of stable QDs with designed functional structures has long been challenging. Here, we propose a strategy for three-dimensional direct lithography of desired QDs within a hybrid medium with specific protection properties. The acrylate-functionalized hybrid precursors enable local crosslinking through ultrafast laser-induced multiphoton absorption, achieving sub-100 nm resolution surpassing the diffraction limit. The printed micro-/nano- structures possess thermal stability up to 600°C, which can be transformed to inorganic architectures with a volume shrinkage. Due to the encapsulated QDs within the densely silicon-oxygen molecular networks, the functional structures demonstrate good stability against ultraviolet irradiation, corrosive solutions, and elevated temperatures. Based on hybrid 3D nanolithography, bicolor multilayer micro-/nano- structures are manufactured for applications in 3D data storage and optical information encryption. This research presents an effective strategy for the fabrication of desired QD micro-/nano- structures, supporting the development of stable functional device applications.

Aluminium surface work hardening enables multi-scale 3D lithography.

Multi-scale structures are ubiquitous in biological systems. However, manufacturing man-made structures with controllable features spanning multiple length scales, particularly down to nanoscale features, is very challenging, which seriously impacts their collective properties. Here we introduce an aluminium-based three-dimensional lithography that combines sequential nano-micro-macro-imprinting and anodization of multi-scale anodic aluminium oxide templates to manufacture well-defined multi-scale structures, using various materials. The high-fidelity nano-patterns and micro-patterns were facilitated by the surface work hardening phenomenon, where the nano-patterns can be further fine-tailored by anodization to have high-aspect-ratio and tunable nano-holes. Based on the aluminium-based three-dimensional lithography, multi-scale materials across length scales of at least 107 orders of magnitude were precisely fabricated, including carbon, semiconductors and metals. We integrated pressure sensors and biosensors with superior and customizable performances by tailoring the multi-scale carbon networks on different length scales from nanofibres and micropyramids to macrodome arrays. This work provides a versatile technique for prototyping on-demand multi-scale structures and materials to explore desirable mechanical and physical properties.

Reliability-Based Design Optimization of Additive Manufacturing for Lithium Battery Silicon Anode

Abstract With the blooming of the electric vehicle market and the advancement in the lithium-ion battery industry, silicon anode has shown great potential for the next-generation battery. Using the state-of-the-art additive manufacturing technique (three-dimensional (3D) holographic lithography), researchers have demonstrated that silicon anode can be fabricated as a three-dimensional bicontinuous porous microstructure. However, the volume fluctuation of the silicon anode caused by lithiation during the discharging process causes continuous capacity decay and poor cycling life. Besides, uncertainties are inherent in the manufacturing and usage processes, making it crucial to systematically consider them in the silicon anode design to improve its performance and reliability. To fill the gap between current silicon anode research and future industrial need, this study established a digital twin to investigate the optimal design for silicon anode under the uncertainties of additive manufacturing and battery usage. This study started with developing multiphysics finite element models of the silicon anode lithiation process to investigate the volume fluctuation of silicon. Then, surrogate models were built based on the results from the finite element models to reduce computational cost. The reliability-based design optimization (RBDO) was employed to find the best design point for the silicon anode, in which an outer optimization loop maximized the objective function and an inner loop dedicated to reliability analysis. Finally, the Pareto optimal front of the silicon anode designs was obtained and validated, which shows over 10% improvements in the silicon anode's total capacity and rate capability.

Localized Temperature Engineering Enables Writing of Heterostructures in Glass for Polarized Photoluminescence of Perovskites.

Metal halide perovskite (MHP) structures that exhibit polarized photoluminescence (PL) have attracted significant interest in fabricating light field regulation elements for display, imaging, and information storage applications. We report a three-dimensional direct lithography of heterostructures for controllable polarized PL inside glass by laser-induced localized temperature engineering. The heterostructures consisted of oriented periodic structures (OPSs) and MHP nanocrystals, and the mechanism for hierarchical distribution of heterostructures was illustrated. The patterning of heterostructures for manipulable polarized PL can be used for information encryption, wave-plate, and polarized micro-LEDs.

Simulation study of three-dimensional grayscale ice lithography on amorphous solid water for blazed gratings

Electron beam lithography (EBL) on amorphous solid water (ASW), termed as ice lithography (IL), has demonstrated promising capability in pattern transfer with unique advantages such as reduced proximity effect. So far, ice lithography for binary patterning has been proved a great success, however, application for three-dimensional (3D) profiling in nanoscale has still not been addressed to the best of our knowledge. This paper reports, for the first time, our progress in simulating study of three-dimensional ice lithography on ASW for linear blazed gratings, aiming to overcome the difficulty in replicating high quality blazed gratings with high diffraction efficiency. Systematic simulation of grayscale ice lithography for 3-D blazed grating templates with desired surface quality as the task was carried out, using Monte Carlo algorithm based on the measured contrast curves of ASW. For comparison, grayscale electron beam lithography on PMMA was also performed. The resultant profiles of blazed wavelengths around 1550 nm by grayscale IL show less flaws and higher diffraction efficiencies than by EBL. The successful simulation of 3D grayscale IL provides us with instructive guide for the fabrication of 3D nanostructures as a whole through the grayscale ice lithography on ASW.

Precise control of the optical refractive index in nanolattices

Recent developments in photonic devices, light field display, and wearable electronics have resulted from a competitive development toward new technologies to improve the user experience in the field of optics. These advances can be attributed to the rise of nanophotonics and meta-surfaces, which can be designed to manipulate light more efficiently. In these elements the performance scales are favorable to the index contrast, making the use of low-index material important. In this research, we examine the precise control of refractive indices of a low-index nanolattice material. This approach employs three-dimensional (3D) lithography and atomic layer deposition (ALD), allowing for precise control of the nanolattice geometry and its refractive index. The refractive indices of the fabricated nanolattices are characterized using spectroscopic ellipsometry and agree well with models based on effective medium theory. By controlling the unit-cell geometry by the exposure conditions and the shell thickness by the ALD process, the effective index of the nanolattice film can be precisely controlled to as low as 5 × 10−4. The proposed index control technique opens a gamut of opportunities and enables better performance in nanophotonic elements used in displays and other integrated devices.

Three-dimensional plasmonic lithography imaging modeling based on the RCWA algorithm for computational lithography.

This paper reminds the principle and characteristics of plasmonic lithography, and points out the importance of establishing a fast and high precision plasmonic lithography imaging model and developing computational lithography. According to the characteristics of plasmonic lithography, the rigorous coupled-wave analysis (RCWA) algorithm is a very suitable alternative algorithm. In this paper, a three-dimensional plasmonic lithography model based on RCWA algorithm is established for computational lithography requirements. This model improves the existing RCWA algorithm, that is, deduces the formula for calculating the light field inside the structure and proposes the integration, storage and invocation of the scattering matrix to improve the computation speed. Finally, the results are compared with commercial software for the two typical patterns. The results show that the two calculation results are very close, with the root mean square error (RMSE) less than 0.04 (V/m)2. In addition, the calculation speed can be increased by more than 2 times in the first calculation, and by about 8 times by integrating, storing and invoking the scattering matrix, which creates conditions for the development of plasmonic computational lithography.

Three-dimensional direct lithography of stable perovskite nanocrystals in glass.

Material composition engineering and device fabrication of perovskite nanocrystals (PNCs) in solution can introduce organic contamination and entail several synthetic, processing, and stabilization steps. We report three-dimensional (3D) direct lithography of PNCs with tunable composition and bandgap in glass. The halide ion distribution was controlled at the nanoscale with ultrafast laser-induced liquid nanophase separation. The PNCs exhibit notable stability against ultraviolet irradiation, organic solution, and high temperatures (up to 250°C). Printed 3D structures in glass were used for optical storage, micro-light emitting diodes, and holographic displays. The proposed mechanisms of both PNC formation and composition tunability were verified.

Субволновые текстурированные поверхности для вывода излучения из волновода

A technology for creating textured surfaces by focused-beam ion-beam etching on GaAs (100) substrates is demonstrated. The possibility of flexible control of the shape and profile of the formed submicron elements of textured media is shown. It will make possible to create textured surfaces of almost any complexity for the implementation of surface output of radiation from a waveguide. Original lithographic templates were developed and three-dimensional lithography was carried out. The control of the formed lithographic patterns was carried out by the methods of optical, electron and atomic force microscopy.

High laser induced damage threshold photoresists for nano-imprint and 3D multi-photon lithography

Abstract Optics manufacturing technology is predicted to play a major role in the future production of integrated photonic circuits. One of the major drawbacks in the realization of photonic circuits is the damage of optical materials by intense laser pulses. Here, we report on the preparation of a series of organic–inorganic hybrid photoresists that exhibit enhanced laser-induced damage threshold. These photoresists showed to be candidates for the fabrication of micro-optical elements (MOEs) using three-dimensional multiphoton lithography. Moreover, they demonstrate pattern ability by nanoimprint lithography, making them suitable for future mass production of MOEs.

An Improved Transwell Design for Microelectrode Ion-Flux Measurements.

The microelectrode ion flux estimation (MIFE) is a powerful, non-invasive electrophysiological method for cellular membrane transport studies. Usually, the MIFE measurements are performed in a tissue culture dish or directly with tissues (roots, parts of the plants, and cell tissues). Here, we present a transwell system that allows for MIFE measurements on a cell monolayer. We introduce a measurement window in the transwell insert membrane, which provides direct access for the cells to the media in the upper and lower compartment of the transwell system and allows direct cell-to-cell contact coculture. Three-dimensional multiphoton lithography (MPL) was used to construct a 3D grid structure for cell support in the measurement window. The optimal polymer grid constant was found for implementation in transwell MIFE measurements. We showed that human umbilical vein endothelial cells (HUVECs) efficiently grow and maintain their physiological response on top of the polymer structures.

Three-Dimensional Optical Lithography and Nanoscale Optical Connectors

Three-dimensional optical connectors for connecting planar waveguides made of silicon are created via direct laser writing. The morphology and optical properties of the resulting structures are compared. Hybrid three-dimensional optical connectors can be used to transmit the light from effective sources of single photons based on colloidal quantum dots and substituted nitrogen and silicon vacancies (NV and Si centers) in diamond, which can be incorporated into a polymer printed wiring board during its manufacture, to planar waveguides for subsequent use in photonic integrated circuits.

Microfluidic Device Fabricated by Three-Dimensional Lithography for Observation of Cancer Cell Invasion Process

Microfluidic Device Fabricated by Three-Dimensional Lithography for Observation of Cancer Cell Invasion Process

Multi-scale, multi-depth lithography using optical fibers for microfluidic applications

This paper proposes and demonstrates a method for multi-scale, multi-depth three-dimensional (3D) lithography. In this method, 3D molds for replicating microchannels are fabricated by passing a non-focused laser beam through an optical fiber, whose tip is immersed in a droplet of photopolymer. Line width is adjustable from 1 to 980 µm using eight kinds of optical fibers with different core diameters. The height of line drawing can be controlled by adjusting the distance between the tip of the optical fiber and a substrate. The surface roughness (Ra, Rz) of a single line and plane was evaluated. The method was employed to fabricate a 3D mold of a microchannel containing tandem chambers, which was then successfully replicated in PDMS. Multi-scale, multi-depth 3D lithography can provide a simple, flexible tool for producing PDMS microfluidic devices.

Fabrication of ionic liquid-based pressure sensor with high sensitivity utilizing three-dimensional lithography and its characterization

Fabrication of ionic liquid-based pressure sensor with high sensitivity utilizing three-dimensional lithography and its characterization

Three-dimensional photolithography using built-in lens mask

Three-dimensional lithography processes are required to fabricate the complex structures of advanced MEMS devices. The built-in lens mask has a complex transmittance amplitude and emulates the optical wave planes of arbitrarily shaped images that are to be focused on a focal plane. In our previous work, the authors proposed a novel three-dimensional imaging method using a multifocusing built-in lens mask in a computational simulation study. In this work, the authors study the three-dimensional photolithography process experimentally using this built-in lens mask. A pyramidal frame pattern is used to expose a negative thick resist layer (SU-8), and three-dimensional structures are successfully obtained using a single mask and a single-shot photolithography process. The experimental results agree fairly well with those from the computational simulations.

Characterization of three-dimensional field distribution of bowtie aperture using quasi-spherical waves and surface plasmon polaritons

We present an analytical formula to predict the three-dimensional field distribution of a nanoscale bowtie aperture using quasi-spherical waves (QSWs) and surface plasmon polaritons, which are excited by the fundamental waveguide mode and local plasmons of the aperture, respectively. Assuming two separate bowtie apertures in a metal film, we analysed the decay characteristics of QSWs using a finite difference time-domain method. To verify the formula, we recorded the spot patterns of the bowtie aperture on a photoresist film using various exposure times, and fit the patterns to the analytical formula in terms of the width and depth of the patterns. In addition, it was found that the formula successfully represented the dipole characteristics of the spot patterns, which were in agreement with the surface geometry, with a root-mean-square error of 9.4%. We expect that our theoretical formula will extend the potential applications of nanoscale bowtie apertures to plasmonic device fabrication, three-dimensional plasmonic lithography, and other technologies.

タルボット効果を用いた広範囲3次元リソグラフィ（第1報） 波面制御および定在波を援用した機能性構造の作製

タルボット効果を用いた広範囲3次元リソグラフィ（第1報） 波面制御および定在波を援用した機能性構造の作製

Microactuation and sensing using reversible deformations of laser-written polymeric structures

We investigate reversible deformations of polymeric microstructures fabricated using direct laser writing three-dimensional lithography upon immersion in various solvents. Swelling and shrinkage of sub-micrometre size features are induced by interaction with surrounding solvent and such deformations can be exploited to create larger structures whose size, shape, and other structural parameters depend on the surroundings. We describe diffractive optical elements, micro-mechanical sensors and also hybrid deformable structures, that can be used to implement micro-actuation, micro-sensing, and other functionalities highly sought for micro-optical, micro-mechanical, and micro-fluidic systems.

Synthesis of metallic nanoparticles through X-ray radiolysis using synchrotron radiation

The potential to fabricate metallic nanoparticles directly on silicon substrates from liquid solutions is ideal for three-dimensional lithography systems, drug delivery materials, and sensing applications. Here, we report the successful synthesis of Au, Cu, and Fe nanoparticles from the corresponding liquid solutions [gold(I) trisodium disulphite, copper(II) sulfate, and potassium ferricyanide] by synchrotron (SR) X-ray irradiation. The deposition of gold nanoparticles in the gold(I) trisodium disulphite solution was performed by monochromatic X-ray exposure from synchrotron radiation. The use of ethanol as an additive enabled the nucleation and growth of Cu particles, while no Cu particles were produced in the copper sulfate solution without ethanol with polychromatic SR X-ray irradiation. Fe particles were generated by direct polychromatic SR X-ray irradiation. These results demonstrate the behavior of three-dimensional printers, enabling us to build composite material structures with metallic and plastic materials.