Name: Metal-Assisted Electrochemical Nanoimprinting of Porous and Solid Silicon Wafers (Video) | JoVE Journal
Uploaded: 2022-02-08T12:30:00.000+00:00
Duration: 9 min 18 s
Description: Discover metal-assisted electrochemical nanoimprinting for creating 3D hierarchical microstructures in silicon wafers with sub-100 nm resolution. This method enables advanced optical device fabrication.

ai_agent_IP

ai_agent

maintenance

instantTrialDurationMinutes

isBiopharma

enableNewMyJoveSectionDesign

educationFeatures

seoMetaApi

ai_copilot_institution_blacklist

ai_chat_institution_blacklist

freeAccessWindow

ssoRoleCapture

scheduledMaintenanceBanner

joveLabsFeatures

disable_autoplay_for_bots

extended_trial_duration

5 minutes

We acknowledge Dr. Keng Hsu (University of Louisville) for insights regarding this work; University of Illinois&#39;s Frederick Seitz Laboratory and, in memoriam, staff member Scott Maclaren; Arizona State University&#39;s LeRoy Eyring Center for Solid State Science; and the Science Foundation Arizona under the Bis grove Scholars Award.

<ol><li>Ning, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Transfer-Printing+of+Tunable+Porous+Silicon+Microcavities+with+Embedded+Emitters%5BTitle%5D)+AND+%22ACS+Photonics%22%5BJournal%5D)">Transfer-Printing of Tunable Porous Silicon Microcavities with Embedded Emitters.</a> ACS Photonics. 1 (11), 1144-1150 (2014).</li>
<li>Hirschman, K. D., Tsybeskov, L., Duttagupta, S. P., Fauchet, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Silicon-based+light+emitting+devices+integrated+into+microelectronic+circuits%5BTitle%5D)+AND+%22Nature%22%5BJournal%5D)">Silicon-based light emitting devices integrated into microelectronic circuits.</a> Nature. 384, 338-341 (1996).</li>
<li>Cho, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Nanoscale+Origami+for+3D+Optics%5BTitle%5D)+AND+%22Small%22%5BJournal%5D)">Nanoscale Origami for 3D Optics.</a> Small. 7 (14), 1943-1948 (2011).</li>
<li>Azeredo, B. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Silicon+nanowires+with+controlled+sidewall+profile+and+roughness+fabricated+by+thin-film+dewetting+and+metal-assisted+chemical+etching%5BTitle%5D)+AND+%22Nanotechnology%22%5BJournal%5D)">Silicon nanowires with controlled sidewall profile and roughness fabricated by thin-film dewetting and metal-assisted chemical etching.</a> Nanotechnology. 24 (22), 225305-225312 (2013).</li>
<li>Lin, C., Tsai, M., Wei, W., Lai, K., He, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Packaging+Glass+with+a+Hierarchically+Nanostructured+Surface%3A+a+universal+method+to+achieve+selfcleaning+omnidirectional+solar+cells%5BTitle%5D)+AND+%22ACS+Nano%22%5BJournal%5D)">Packaging Glass with a Hierarchically Nanostructured Surface: a universal method to achieve selfcleaning omnidirectional solar cells.</a> ACS Nano. 10 (1), 549-555 (2016).</li>
<li>Park, K. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Nanotextured+Silica+Surfaces+with+Robust+Superhydrophobicity+and+Omnidirectional+Broadband+Supertransmissivity%5BTitle%5D)+AND+%22ACS+Nano%22%5BJournal%5D)">Nanotextured Silica Surfaces with Robust Superhydrophobicity and Omnidirectional Broadband Supertransmissivity.</a> ACS Nano. 6 (5), 3789-3799 (2012).</li>
<li>Kim, J., Joy, D. C., Lee, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Controlling+resist+thickness+and+etch+depth+for+fabrication+of+3D+structures+in+electron-beam+grayscale+lithography%5BTitle%5D)+AND+%22Microelectronics+Engineering%22%5BJournal%5D)">Controlling resist thickness and etch depth for fabrication of 3D structures in electron-beam grayscale lithography.</a> Microelectronics Engineering. 84 (12), 2859-2864 (2007).</li>
<li>Deng, S., Zhang, Y., Jiang, S., Lu, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Fabrication+of+three-dimensional+silicon+structure+with+smooth+curved+surfaces%5BTitle%5D)+AND+%22Journal+of+Micro%2FNanolithography%2C+MEMS%2C+and+MOEMS%22%5BJournal%5D)">Fabrication of three-dimensional silicon structure with smooth curved surfaces.</a> Journal of Micro/Nanolithography, MEMS, and MOEMS. 15 (3), 0345031-0345036 (2016).</li>
<li>Azeredo, B. P., Lin, Y., Avagyan, A., Sivaguru, M., Hsu, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Direct+Imprinting+of+Porous+Silicon+via+Metal-Assisted+Chemical+Etching%5BTitle%5D)+AND+%22Advanced+Functional+Materials%22%5BJournal%5D)">Direct Imprinting of Porous Silicon via Metal-Assisted Chemical Etching.</a> Advanced Functional Materials. 26 (17), 2929-2939 (2016).</li>
<li>Azeredo, B., Hsu, K., Ferreira, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Direct+Electrochemical+Imprinting+of+Sinusoidal+Linear+Gratings+into+Silicon%5BTitle%5D)+AND+%22The+American+Society+of+Mechanical+Engineers+-+International+Manufacturing+Science+and+Engineering+Conference%22%5BJournal%5D)">Direct Electrochemical Imprinting of Sinusoidal Linear Gratings into Silicon.</a> The American Society of Mechanical Engineers - International Manufacturing Science and Engineering Conference. , 1-6 (2016).</li>
<li>Li, H., Niu, J., Wang, G., Wang, E., Xie, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Direct+Production+of+Silicon+Nanostructures+with+Electrochemical+Nanoimprinting%5BTitle%5D)+AND+%22ACS+Applied+Electronic+Materials%22%5BJournal%5D)">Direct Production of Silicon Nanostructures with Electrochemical Nanoimprinting.</a> ACS Applied Electronic Materials. 1 (7), 1070-1075 (2019).</li>
<li>Kim, K., Ki, B., Choi, K., Lee, S., Oh, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Resist-Free+Direct+Stamp+Imprinting+of+GaAs+via+Metal-Assisted+Chemical+Etching%5BTitle%5D)+AND+%22ACS+Applied+Materials+%26+Interfaces%22%5BJournal%5D)">Resist-Free Direct Stamp Imprinting of GaAs via Metal-Assisted Chemical Etching.</a> ACS Applied Materials & Interfaces. 11 (14), 13574-13580 (2019).</li>
<li>Zhang, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Contact+electrification+induced+interfacial+reactions+and+direct+electrochemical+nanoimprint+lithography+in+n-type+gallium+arsenate+wafer%5BTitle%5D)+AND+%22Chemical+Science%22%5BJournal%5D)">Contact electrification induced interfacial reactions and direct electrochemical nanoimprint lithography in n-type gallium arsenate wafer.</a> Chemical Science. 8, 2407-2412 (2017).</li>
<li>Zhan, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Electrochemical+micro%2Fnano-machining%3A+principles+and+practices%5BTitle%5D)+AND+%22Chemical+Society+Reviews%22%5BJournal%5D)">Electrochemical micro/nano-machining: principles and practices.</a> Chemical Society Reviews. 46 (5), 1526-1544 (2017).</li>
<li>Li, X., Bohn, P. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Metal-assisted+chemical+etching+in+HF+%2F+H2O2+produces+porous+silicon%5BTitle%5D)+AND+%22Applied+Physics+Letters%22%5BJournal%5D)">Metal-assisted chemical etching in HF / H2O2 produces porous silicon.</a> Applied Physics Letters. 77 (16), 2572-2574 (2000).</li>
<li>Chartier, C., Bastide, S., Levy-Clement, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Metal-assisted+chemical+etching+of+silicon+in+HF+-+H2O2%5BTitle%5D)+AND+%22Electrochimica+Acta%22%5BJournal%5D)">Metal-assisted chemical etching of silicon in HF - H2O2.</a> Electrochimica Acta. 53, 5509-5516 (2008).</li>
<li>Chattopadhyay, S., Li, X., Bohn, P. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((In-plane+control+of+morphology+and+tunable+photoluminescence+in+porous+silicon+produced+by+metal-assisted+electroless+chemical+etching%5BTitle%5D)+AND+%22Journal+of+Applied+Physics%22%5BJournal%5D)">In-plane control of morphology and tunable photoluminescence in porous silicon produced by metal-assisted electroless chemical etching.</a> Journal of Applied Physics. 91 (9), 6134-6140 (2002).</li>
<li>Torralba, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((3D+patterning+of+silicon+by+contact+etching+with+anodically+biased+nanoporous+gold+electrodes%5BTitle%5D)+AND+%22Electrochemistry+Communications%22%5BJournal%5D)">3D patterning of silicon by contact etching with anodically biased nanoporous gold electrodes.</a> Electrochemistry Communications. 76, 79-82 (2017).</li>
<li>Bastide, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((3D+Patterning+of+Si+by+Contact+Etching+With+Nanoporous+Metals%5BTitle%5D)+AND+%22Frontiers+in+Chemistry%22%5BJournal%5D)">3D Patterning of Si by Contact Etching With Nanoporous Metals.</a> Frontiers in Chemistry. 7, 1-13 (2019).</li>
<li>Sharstniou, A., Niauzorau, S., Ferreira, P. M., Azeredo, B. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Electrochemical+nanoimprinting+of+silicon%5BTitle%5D)+AND+%22Proceedings+of+the+National+Academy+of+Sciences%22%5BJournal%5D)">Electrochemical nanoimprinting of silicon.</a> Proceedings of the National Academy of Sciences. 116 (21), 10264-10269 (2019).</li>
<li>Niauzorau, S., Ferreira, P., Azeredo, B. Synthesis of Porous Noble Metal Films with Tunable Porosity by Timed Dealloying. The American Society of Mechanical Engineers - International Manufacturing Science and Engineering Conference. , 1-4 (2018).</li>
<li>Geyer, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Model+for+the+Mass+Transport+During+Metal-Assisted+Chemical+Etching+with+Contiguous+Metal+Films+As+Catalysts%5BTitle%5D)+AND+%22The+Journal+of+Physical+Chemistry+C%22%5BJournal%5D)">Model for the Mass Transport During Metal-Assisted Chemical Etching with Contiguous Metal Films As Catalysts.</a> The Journal of Physical Chemistry C. 116 (24), 13446-13451 (2012).</li>
<li>Li, L., Liu, Y., Zhao, X., Lin, Z., Wong, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Uniform+Vertical+Trench+Etching+on+Silicon+with+High+Aspect+Ratio+by+Metal-Assisted+Chemical+Etching+Using+Nanoporous+Catalysts%5BTitle%5D)+AND+%22ACS+Applied+Materials+and+Interfaces%22%5BJournal%5D)">Uniform Vertical Trench Etching on Silicon with High Aspect Ratio by Metal-Assisted Chemical Etching Using Nanoporous Catalysts.</a> ACS Applied Materials and Interfaces. 6 (1), 575-584 (2014).</li>
</ol>

We do not have anything to disclose.

Mac-Imprint stamps and prepatterned Si chips (p-type, [100] orientation, 1-10 Ohm&#8729;cm) were prepared according to sections 1 and 2 of the protocol, respectively. The Mac-Imprint of prepatterned Si chip with stamps containing 3D hierarchical patterns was performed according to section 3 of the protocol (Figure 9). As shown in Figure 9a, different configurations of Mac-Imprint were applied: solid Si with solid Au (left), porous Si with solid ...

Three-dimensional micro- and nanoscale patterning and texturization of semiconductors enables numerous applications in various areas, such as optoelectronics1,2, photonics3, antireflective surfaces4, super hydrophobic, and self-cleaning surfaces5,6 among others. Prototyping and mass-producing 3D and hierarchical patterns has been successfully accomplished for polymeric films by soft lithography and nanoimprinting lithography with sub-20 nm resolution. However, transferring such 3D polymeric patterns into Si requires the etching selectivity of a mask pattern during reactive ion etching and thus limits the aspect ratio, and induces shape distortions and surface roughness due to scalloping effects7,8.
A new method called Mac-Imprint has been achieved for parallel and direct patterning of porous9 and solid Si wafers10,11 as well as solid GaAs wafers12,13,14. Mac-Imprint is a contact-based wet etching technique that requires contact between substrate and a noble metal-coated stamp possessing 3D features in the presence of an etching solution (ES) composed of HF and an oxidant (e.g., H2O2 in the case of Si Mac-Imprint). During the etching, two reactions occur simultaneously15,16: a cathodic reaction (i.e., the H2O2 reduction at the noble metal, during which positive charge carriers [holes] are generated and subsequently injected into Si17) and an anodic reaction (i.e., Si dissolution, during which the holes are consumed). After sufficient time in contact, the stamp's 3D features are etched into the Si wafer. Mac-Imprint has numerous advantages over conventional lithographical methods, such as high throughput, compatibility with roll-to-plate and roll-to-roll platforms, amorphous, mono- and polycrystalline Si and III-V semiconductors. Mac-Imprint stamps can be reused multiple times. Additionally, the method can deliver a sub-20 nm etching resolution that is compatible with contemporary direct writing methods.
The key to attaining high-fidelity imprinting is the diffusion pathway to the etching front (i.e., contact interface between catalyst and substrate). The work of Azeredo et al.9 first demonstrated that ES diffusion is enabled through a porous Si network. Torralba et al.18, reported that in order to realize solid Si Mac-Imprint the ES diffusion is enabled through a porous catalyst. Bastide et al.19 and Sharstniou et al.20 further investigated the catalyst porosity influence on ES diffusion. Thus, the concept of Mac-Imprint has been tested in three configurations with distinct diffusion pathways.
In the first configuration, the catalyst and substrate are solid, providing no initial diffusion pathway. The lack of reactant diffusion leads to a secondary reaction during imprinting that forms a layer of porous Si on the substrate around the edge of the catalyst-Si interface. The reactants are subsequently depleted, and the reaction stops, resulting in no discernable pattern transfer fidelity between the stamp and substrate. In the second and third configurations, the diffusion pathways are enabled through porous networks introduced either in the substrate (i.e., porous Si) or in the catalyst (i.e., porous gold) and high pattern transfer accuracy is attained. Thus, the mass transport through porous materials plays a critical role in enabling the diffusion of reactants and reaction products to and away from the contact interface9,18,19,20. A schematic of all three configurations is shown in Figure 1.
<img alt="Silicon etching diagram with diffusion, porous catalyst, illustrating porosity-enabled selective etching." class="xfigimg" src="/files/ftp_upload/61040/61040fig1.jpg" data-altupdatedat="1788250015000" data-alt="Figure 1"> 
Figure 1: Schematics of Mac-Imprint configurations. This figure highlights the role of porous materials in enabling the diffusion of reacting species through the substrate (i.e., case II: porous Si) or in the stamp (i.e., case III: catalyst thin film made of porous gold). <a href="https://www.jove.com/files/ftp_upload/61040/61040fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
In this paper, the Mac-Imprint process is thoroughly discussed, including stamp preparation and substrate pretreatment along with Mac-Imprint itself. The substrate pretreatment section within the protocol includes Si wafer cleaning and Si wafer patterning with dry etching and substrate anodization (optional). Further, a stamp preparation section is subdivided into several procedures: 1) PDMS replica molding of Si master mold; 2) UV nanoimprinting of a photoresist layer in order to transfer the PDMS pattern; and 3) catalytic layer deposition via magnetron sputtering followed by dealloying (optional). Finally, in the Mac-Imprint section the Mac-Imprint setup along with the Mac-Imprint results (i.e., Si surface 3D hierarchical patterning) is presented.

<table><tbody><tr><td>Acetone, &gt;99.5%, ACS reagent</td><td>Sigma-Aldrich</td><td>67-64-1</td><td>CAUTION, chemical</td></tr><tr><td>Ammonium fluoride, &gt;98%, ACS grade</td><td>Sigma-Aldrich</td><td>12125-01-8</td><td>CAUTION, hazardous</td></tr><tr><td>Ammonium hydroxide solution, 28-30%, ACS reagent</td><td>Sigma-Aldrich</td><td>1336-21-6</td><td>CAUTION, hazardous</td></tr><tr><td>AZ 400K developer</td><td>Microchemicals</td><td>AZ 400K</td><td>CAUTION, chemical</td></tr><tr><td>BenchMark 800 Etch</td><td>Axic</td><td>BenchMark 800</td><td>Reactive ion etching</td></tr><tr><td>Chromium target, 2&quot; x 0.125&quot;, 99.95% purity</td><td>ACI alloys</td><td>ADM0913</td><td>Magnetron sputter chromium target</td></tr><tr><td>CTF 12</td><td>Carbolite Gero</td><td>C12075-700-208SN</td><td>Tube furnace</td></tr><tr><td>Desiccator</td><td>Fisher scientific Chemglass life sciences</td><td>CG122611</td><td>Desiccator</td></tr><tr><td>F6T5/BLB</td><td>Eiko</td><td>F6T5/BLB 6W</td><td>UV bulb</td></tr><tr><td>Gold target, 2&quot; x 0.125&quot;, 99.99% purity</td><td>ACI alloys</td><td>N/A</td><td>Magnetron sputter gold target</td></tr><tr><td>Hotplate KW-4AH</td><td>Chemat Technology</td><td>KW-4AH</td><td>Leveled hotplate with uniform temperature profile</td></tr><tr><td>Hydrofluoric acid, 48%, ACS reagent</td><td>Sigma-Aldrich</td><td>7664-39-3</td><td>CAUTION, extremly hazardous</td></tr><tr><td>Hydrogen peroxide, 30%, ACS reagent</td><td>Fisher Chemical</td><td>7722-84-1</td><td>CAUTION, hazardous</td></tr><tr><td>Isopropyl alcohol, &gt;99.5%, ACS reagent</td><td>LabChem</td><td>67-63-0</td><td>CAUTION, chemical</td></tr><tr><td>MLP-50</td><td>Transducer Techniques</td><td>MLP-50</td><td>Load cell</td></tr><tr><td>Nitric acid, 70%, ACS grade</td><td>SAFC</td><td>7697-37-2</td><td>CAUTION, hazardous</td></tr><tr><td>NSC-3000</td><td>Nano-master</td><td>NSC-3000</td><td>Magnetron sputter</td></tr><tr><td>Potassium hydroxide, 45%, Certified</td><td>Fisher Chemical</td><td>1310-58-3</td><td>CAUTION, chemical</td></tr><tr><td>Rocker 800 vacuum pump, 110V/60Hz</td><td>Rocker</td><td>1240043</td><td>Oil-free vacuum pump</td></tr><tr><td>Silicon master mold</td><td>NILT</td><td>SMLA_V1</td><td>Silicon chip with pattern</td></tr><tr><td>Silicon wafers, prime grade</td><td>University wafer</td><td>783</td><td>Si wafer</td></tr><tr><td>Silver target, 2&quot; x 0.125&quot;, 99.99% purity</td><td>ACI alloys</td><td>HER2318</td><td>Magnetron sputter silver target</td></tr><tr><td>SP-300</td><td>BioLogic</td><td>SP-300</td><td>Potentiostat</td></tr><tr><td>SPIN 150i</td><td>Spincoating</td><td>SPIN 150i</td><td>Spin coater</td></tr><tr><td>SPR 200-7.0 positive photoresist</td><td>Microchem</td><td>SPR 220-7.0</td><td>CAUTION, chemical</td></tr><tr><td>Stirring hotplate</td><td>Thermo scientific Cimarec+</td><td>SP88857100</td><td>General purpose hotplate</td></tr><tr><td>SU-8 2015 negative photoresist</td><td>Microchem</td><td>SU-8 2015</td><td>CAUTION, chemical</td></tr><tr><td>SYLGARD 184 Silicone elastomer kit</td><td>DOW</td><td>4019862</td><td>CAUTION, chemical</td></tr><tr><td>T-LSR150B</td><td>Zaber Technologies</td><td>T-LSR150B-KT04U</td><td>Motorized linear stage</td></tr><tr><td>Trichloro(1H,1H,2H,2H-perfluorooctyl)silane (PFOCS), 97%</td><td>Sigma-Aldrich</td><td>78560-45-9</td><td>CAUTION, hazardous</td></tr></tbody></table>

metal-assisted electrochemical nanoimprinting of porous and solid silicon wafers

Metal-Assisted Electrochemical Nanoimprinting of Porous and Solid Silicon Wafers

Metal-assisted electrochemical imprinting (Mac-Imprint) is a combination of metal-assisted chemical etching (MACE) and nanoimprint lithography that is capable of direct patterning 3D micro- and nanoscale features in monocrystalline group IV (e.g., Si) and III-V (e.g., GaAs) semiconductors without the need of sacrificial templates and lithographical steps. During this process, a reusable stamp coated with a noble metal catalyst is brought in contact with a Si wafer in the presence of a hydrofluoric acid (HF) and hydrogen peroxide (H2O2) mixture, which leads to the selective etching of Si at the metal-semiconductor contact interface. In this protocol, we discuss the stamp and substrate preparation methods applied in two Mac-Imprint configurations: (1) Porous Si Mac-Imprint with a solid catalyst; and (2) Solid Si Mac-Imprint with a porous catalyst. This process is high throughput and is capable of centimeter-scale parallel patterning with sub-20 nm resolution. It also provides low defect density and large area patterning in a single operation and bypasses the need for dry etching such as deep reactive ion etching (DRIE).

Scanning electron microscope (SEM) images, optical microscope scans (Figure 9), and atomic force microscopy (AFM) scans (Figure 10) were obtained in order to study the morphological properties of the Mac-Imprint stamps and imprinted Si surfaces. The cross-sectional profile of the imprinted solid Si was compared to that of the used porous Au stamp (Figure 10). Pattern transfer fidelity and porous Si g...

A protocol for metal-assisted chemical imprinting of 3D microscale features with sub-20 nm shape accuracy into solid and porous silicon wafers is presented.

Metal-assisted electrochemical imprinting (Mac-Imprint) is a combination of metal-assisted chemical etching (MACE) and nanoimprint lithography that is ...

metal-assisted-electrochemical-nanoimprinting-porous-solid-silicon

Research

JoVE Journal

Engineering

Here we describe a simple method for patterning oxide-free silicon and germanium with reactive organic monolayers and demonstrate functionalization of the patterned substrates with small molecules and proteins. The approach completely protects surfaces from chemical oxidation, provides precise control over feature morphology, and provides ready access to chemically discriminated patterns.

Soft Lithographic Functionalization and Patterning Oxide-free Silicon and Germanium

We describe a nanomoulding technique which allows low-cost nanoscale patterning of functional materials, materials stacks and full devices. Nanomoulding can be performed on any nanoimprinting setup and can be applied to a wide range of materials and deposition processes.

Nanomoulding of Functional Materials, a Versatile Complementary Pattern Replication Method to Nanoimprinting

This protocol describes the use of microscale silicon cantilevers as pliable culture surfaces for measuring the contractility of muscle cells in vitro. Cellular contraction causes cantilever bending, which can be measured, recorded, and converted into readouts of force, providing a non-invasive and scalable system for measuring contractile function in vitro.

Utilization of Microscale Silicon Cantilevers to Assess Cellular Contractile Function In Vitro

This paper introduces a 3D additive micromanufacturing strategy (termed ‘micro-masonry’) for the flexible fabrication of microelectromechanical system (MEMS) structures and devices. This approach involves transfer printing-based assembly of micro/nanoscale materials in conjunction with rapid thermal annealing-enabled material bonding techniques.

Micro-masonry for 3D Additive Micromanufacturing

A viable transfer printing-based methodology to introduce plasmonic metal nanostructures in solar cells is described.  Using nanopillar poly(dimethylsiloxane) stamps, an Ag-based ordered nanodisk array was integrated with standard hydrogenated microcrystalline Si solar cells, which led to improved device performances due to plasmonic light trapping.

Integration of Light Trapping Silver Nanostructures in Hydrogenated Microcrystalline Silicon Solar Cells by Transfer Printing

We demonstrate a microfluidic platform with an integrated surface electrode network that combines resistive pulse sensing (RPS) with code division multiple access (CDMA), to multiplex detection and sizing of particles in multiple microfluidic channels.

Microfluidic Platform with Multiplexed Electronic Detection for Spatial Tracking of Particles

This report describes a simple, easy to perform technique, using low pressure vacuum, to fill microfluidic channels with cells and substrates for biological research.

A Versatile Method of Patterning Proteins and Cells

Isolating electrical and thermal effects on electrically assisted deformation (EAD) is very difficult using macroscopic samples. Metallic sample micro- and nanostructures together with a custom test procedure have been developed to evaluate the impact of applied current on the formation without joule heating and evolution of dislocations on these samples.

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

We demonstrate the synthesis of fusogenic porous silicon nanoparticles for effective in vitro and in vivo oligonucleotide delivery. Porous silicon nanoparticles are loaded with siRNA to form the core, which is coated by fusogenic lipids through extrusion to form the shell. Targeting moiety functionalization and particle characterization are included.

Synthesis, Functionalization, and Characterization of Fusogenic Porous Silicon Nanoparticles for Oligonucleotide Delivery

This work presents microfabrication protocols for achieving cavities and pillars with reentrant and doubly reentrant profiles on SiO2/Si wafers using photolithography and dry etching. Resulting microtextured surfaces demonstrate remarkable liquid repellence, characterized by robust long-term entrapment of air under wetting liquids, despite the intrinsic wettability of silica.

Rendering SiO2/Si Surfaces Omniphobic by Carving Gas-Entrapping Microtextures Comprising Reentrant and Doubly Reentrant Cavities or Pillars

Presented here is a stepwise protocol for realizing gas-entrapping membranes (GEMs) from SiO2/Si wafers using integrated circuit microfabrication technology. When silica-GEMs are immersed in water, the intrusion of water is prevented, despite the water-loving composition of silica.

Proof-of-Concept for Gas-Entrapping Membranes Derived from Water-Loving SiO2/Si/SiO2 Wafers for Green Desalination

Discover metal-assisted electrochemical nanoimprinting for creating 3D hierarchical microstructures in silicon wafers with sub-100 nm resolution. This method enables advanced optical device fabrication.

Metal-Assisted Electrochemical Nanoimprinting of Porous and Solid Silicon Wafers

Explore More Videos