Nanosphere lithography

Last updated

Nanosphere lithography (NSL) is an economical technique for generating single-layer hexagonally close packed or similar patterns of nanoscale features. Generally, NSL applies planar ordered arrays of nanometer-sized latex or silica spheres as lithography masks to fabricate nanoparticle arrays. [1] NSL uses self-assembled monolayers of spheres (typically made of polystyrene, often available commercially as an aqueous suspension) as evaporation masks. These spheres can be deposited using multiple methods including Langmuir-Blodgett, dip coating, spin coating, solvent evaporation, force-assembly, and air-water interface. [2] [3] [4] [5] This method has been used to fabricate arrays of various nanopatterns, including gold nanodots with precisely controlled spacings. [6]

Contents

Nanosphere monolayer preparation

Monolayers of nanospheres, to be used as lithography masks can be created using multiple methods:

Polystyrene nanoparticle coating done with the Langmuir-Blodgett method Nanoparticle coating.png
Polystyrene nanoparticle coating done with the Langmuir-Blodgett method

Langmuir-Blodgett is a deposition method in which the nanoparticles are placed in a Langmuir-Blodgett Trough floating on an aqueous solution, forming a monolayer. With the help of barriers and surface pressure sensor, the particles are compressed into the desired packing density automatically. The coating is done in this packing density with the help of a motorized dipper while the barriers maintain the desired particle packing density. The benefits of the Langmuir-Blodgett method include a strict control over the particle packing density and coating thickness (mono or multilayers can be created) as well as the ability to coat large homogeneous areas. [3] Mask preparation with the Langmuir-Blodgett method has been demonstrated for example using SiO2 particles [7] and polystyrene particles. [8]

Dip-coating is a simplified version of the Langmuir-Blodgett. In dip coating, the nanosphere packing density isn't controlled but the dipping is performed directly on a colloidal particle solution. Dip coating is an effective method for applications where a precise control over the particle distribution isn't required. [3]

Spin Coating and solvent evaporation methods are capable of producing large areas of particles, but with limited control over the layer homogeneity or thickness. [3]

Solvent evaporation is accomplished via drop coating, and is arguably the simplest method to produce a monolayer of nanospheres, as the spheres are simply dropped onto the substrate and allowed to dry, self-assembling into a monolayer. Sometimes the substrate is placed at an angle [9] or moved in circular motions [10] to help the suspension of spheres spread and wet the entire surface.

Force-assembled monolayers are formed from a dry nanosphere powder, which can typically be obtained by centrifugation of a nanosphere suspension. The powder is then rubbed between two substrates to force them into a monolayer. [2] The substrates are typically coated in a polymer such as polydimethylsiloxane (PDMS) to promote adhesion and spreading of the nanospheres.

The air-water interface method relies on the formation of a monolayer of nanospheres on the surface of a water bath, at the air-water interface. In this method, the substrate is held below the surface of the water, and water is then pumped out to gradually lower the surface. Eventually, the water surface is lowered below the level of the substrates, and the monolayer at the air-water interface is deposited onto the substrate surface. [5]

Lithography Method with Colloidal Mask

Illustration of the four main steps of a NSL process, depicting the sequence of: (a) the deposition of colloidal nano/micro-particles on a surface, which will act as mask; (b) reactive ion etching (RIE) for particle shaping, producing a non-close packed array; (c) material infiltration via physical deposition; (d) lift-off of the colloids leaving only the nano/micro-patterned material in between the particles. Colloidal lithography steps.jpg
Illustration of the four main steps of a NSL process, depicting the sequence of: (a) the deposition of colloidal nano/micro-particles on a surface, which will act as mask; (b) reactive ion etching (RIE) for particle shaping, producing a non-close packed array; (c) material infiltration via physical deposition; (d) lift-off of the colloids leaving only the nano/micro-patterned material in between the particles.

NSL is an easily scalable, high-throughput, and low-cost technique that allows nanoscopic precision in an arbitrarily large area. A lithographic mask can be promptly achieved via particle self-assembly, as previously described, whose pattern resolution is entirely dependent on the colloidal size that can be deposited in high-quality monolayer arrays. The best achieved resolutions in the literature range between 50 nm and 200 nm, which is comparable to that of state-of-the-art conventional-lithography systems. [12] Moreover, the fabricated structures can be produced with a high accuracy on a large scale, as the method is not limited in terms of the deposition area, meaning that it offers the possibility to be adapted to mass production techniques such as roll-to-roll. NSL can also be used with a large range of materials as it uses low-temperature steps (<100 °C), making it ideal for usage with temperature-sensitive materials (e.g., polymeric-based flexible substrates). [13]

The NSL method generally starts by the preparation of the patterning mask, comprising a self-assembled monolayer array of colloidal nano/micro-particles, followed by the nano/micro-structure production. The method usually involves four main steps, as depicted in the sketch, allowing the formation of different geometries. The variety of techniques that can be used for the colloidal array formation, as well as for the subsequent structure production, shows the high versatility of this method for implementation in various applications. For instance, it is a preferential soft-lithography technique to micro-pattern photovoltaic devices, to produce structures allowing light-management [13] [14] and/or self-cleaning. [15] [16]

See also

Related Research Articles

A monolayer is a single, closely packed layer of entities, commonly atoms or molecules. Monolayers can also be made out of cells. Self-assembled monolayers form spontaneously on surfaces. Monolayers of layered crystals like graphene and molybdenum disulfide are generally called 2D materials.

<span class="mw-page-title-main">Self-assembly</span> Process in which disordered components form an organized structure or pattern

Self-assembly is a process in which a disordered system of pre-existing components forms an organized structure or pattern as a consequence of specific, local interactions among the components themselves, without external direction. When the constitutive components are molecules, the process is termed molecular self-assembly.

<span class="mw-page-title-main">Colloidal gold</span> Suspension of gold nanoparticles in a liquid

Colloidal gold is a sol or colloidal suspension of nanoparticles of gold in a fluid, usually water. The colloid is coloured usually either wine red or blue-purple . Due to their optical, electronic, and molecular-recognition properties, gold nanoparticles are the subject of substantial research, with many potential or promised applications in a wide variety of areas, including electron microscopy, electronics, nanotechnology, materials science, and biomedicine.

<span class="mw-page-title-main">Nanoparticle</span> Particle with size less than 100 nm

A nanoparticle or ultrafine particle is a particle of matter 1 to 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 100 nm in only two directions. At the lowest range, metal particles smaller than 1 nm are usually called atom clusters instead.

<span class="mw-page-title-main">Self-assembled monolayer</span>

Self-assembled monolayers (SAM) of organic molecules are molecular assemblies formed spontaneously on surfaces by adsorption and are organized into more or less large ordered domains. In some cases molecules that form the monolayer do not interact strongly with the substrate. This is the case for instance of the two-dimensional supramolecular networks of e.g. perylenetetracarboxylic dianhydride (PTCDA) on gold or of e.g. porphyrins on highly oriented pyrolitic graphite (HOPG). In other cases the molecules possess a head group that has a strong affinity to the substrate and anchors the molecule to it. Such a SAM consisting of a head group, tail and functional end group is depicted in Figure 1. Common head groups include thiols, silanes, phosphonates, etc.

<span class="mw-page-title-main">Langmuir–Blodgett trough</span> Laboratory equipment

A Langmuir–Blodgett trough is an item of laboratory apparatus that is used to compress monolayers of molecules on the surface of a given subphase and to measure surface phenomena due to this compression. It can also be used to deposit single or multiple monolayers on a solid substrate.

Nanolithography (NL) is a growing field of techniques within nanotechnology dealing with the engineering of nanometer-scale structures on various materials.

<span class="mw-page-title-main">Dip-pen nanolithography</span> Scanning probe lithographic technique

Dip pen nanolithography (DPN) is a scanning probe lithography technique where an atomic force microscope (AFM) tip is used to create patterns directly on a range of substances with a variety of inks. A common example of this technique is exemplified by the use of alkane thiolates to imprint onto a gold surface. This technique allows surface patterning on scales of under 100 nanometers. DPN is the nanotechnology analog of the dip pen, where the tip of an atomic force microscope cantilever acts as a "pen", which is coated with a chemical compound or mixture acting as an "ink", and put in contact with a substrate, the "paper".

<span class="mw-page-title-main">Langmuir–Blodgett film</span> Thin film obtained by depositing multiple monolayers onto a surface

A Langmuir–Blodgett (LB) film is a nanostructured system formed when Langmuir films—or Langmuir monolayers (LM)—are transferred from the liquid-gas interface to solid supports during the vertical passage of the support through the monolayers. LB films can contain one or more monolayers of an organic material, deposited from the surface of a liquid onto a solid by immersing the solid substrate into the liquid. A monolayer is adsorbed homogeneously with each immersion or emersion step, thus films with very accurate thickness can be formed. This thickness is accurate because the thickness of each monolayer is known and can therefore be added to find the total thickness of a Langmuir–Blodgett film.

<span class="mw-page-title-main">Nanorod</span>

In nanotechnology, nanorods are one morphology of nanoscale objects. Each of their dimensions range from 1–100 nm. They may be synthesized from metals or semiconducting materials. Standard aspect ratios are 3-5. Nanorods are produced by direct chemical synthesis. A combination of ligands act as shape control agents and bond to different facets of the nanorod with different strengths. This allows different faces of the nanorod to grow at different rates, producing an elongated object.

<span class="mw-page-title-main">Coffee ring effect</span> Capillary flow effect

In physics, a "coffee ring" is a pattern left by a puddle of particle-laden liquid after it evaporates. The phenomenon is named for the characteristic ring-like deposit along the perimeter of a spill of coffee. It is also commonly seen after spilling red wine. The mechanism behind the formation of these and similar rings is known as the coffee ring effect or in some instances, the coffee stain effect, or simply ring stain.

<span class="mw-page-title-main">Janus particles</span> Type of nanoparticle or microparticle

Janus particles are special types of nanoparticles or microparticles whose surfaces have two or more distinct physical properties. This unique surface of Janus particles allows two different types of chemistry to occur on the same particle. The simplest case of a Janus particle is achieved by dividing the particle into two distinct parts, each of them either made of a different material, or bearing different functional groups. For example, a Janus particle may have one half of its surface composed of hydrophilic groups and the other half hydrophobic groups, the particles might have two surfaces of different color, fluorescence, or magnetic properties. This gives these particles unique properties related to their asymmetric structure and/or functionalization.

Plasmonic nanolithography is a nanolithographic process that utilizes surface plasmon excitations such as surface plasmon polaritons (SPPs) to fabricate nanoscale structures. SPPs, which are surface waves that propagate in between planar dielectric-metal layers in the optical regime, can bypass the diffraction limit on the optical resolution that acts as a bottleneck for conventional photolithography.

<span class="mw-page-title-main">Silver nanoparticle</span> Ultrafine particles of silver between 1 nm and 100 nm in size

Silver nanoparticles are nanoparticles of silver of between 1 nm and 100 nm in size. While frequently described as being 'silver' some are composed of a large percentage of silver oxide due to their large ratio of surface to bulk silver atoms. Numerous shapes of nanoparticles can be constructed depending on the application at hand. Commonly used silver nanoparticles are spherical, but diamond, octagonal, and thin sheets are also common.

<span class="mw-page-title-main">Sarfus</span> Optical quantitative imaging technique

Sarfus is an optical quantitative imaging technique based on the association of:

A plasmonic-enhanced solar cell, commonly referred to simply as plasmonic solar cell, is a type of solar cell that converts light into electricity with the assistance of plasmons, but where the photovoltaic effect occurs in another material.

<span class="mw-page-title-main">Brewster angle microscope</span>

A Brewster angle microscope (BAM) is a microscope for studying thin films on liquid surfaces, most typically Langmuir films. In a Brewster angle microscope, both the microscope and a polarized light source are aimed towards a liquid surface at that liquid's Brewster angle, in such a way for the microscope to catch an image of any light reflected from the light source via the liquid surface. Because there is no p-polarized reflection from the pure liquid when both are angled towards it at the Brewster angle, light is only reflected when some other phenomenon such as a surface film affects the liquid surface. The technique was first introduced in 1991.

<span class="mw-page-title-main">Self-assembly of nanoparticles</span> Physical phenomenon

Nanoparticles are classified as having at least one of its dimensions in the range of 1-100 nanometers (nm). The small size of nanoparticles allows them to have unique characteristics which may not be possible on the macro-scale. Self-assembly is the spontaneous organization of smaller subunits to form larger, well-organized patterns. For nanoparticles, this spontaneous assembly is a consequence of interactions between the particles aimed at achieving a thermodynamic equilibrium and reducing the system’s free energy. The thermodynamics definition of self-assembly was introduced by Professor Nicholas A. Kotov. He describes self-assembly as a process where components of the system acquire non-random spatial distribution with respect to each other and the boundaries of the system. This definition allows one to account for mass and energy fluxes taking place in the self-assembly processes.

<span class="mw-page-title-main">Nanoparticle deposition</span> Process of attaching nanoparticles to solid surfaces

Nanoparticle deposition refers to the process of attaching nanoparticles to solid surfaces called substrates to create coatings of nanoparticles. The coatings can have a monolayer or a multilayer and organized or unorganized structure based on the coating method used. Nanoparticles are typically difficult to deposit due to their physical properties.

<span class="mw-page-title-main">Liquid marbles</span>

Liquid marbles are non-stick droplets wrapped by micro- or nano-metrically scaled hydrophobic, colloidal particles ; representing a platform for a diversity of chemical and biological applications. Liquid marbles are also found naturally; aphids convert honeydew droplets into marbles. A variety of non-organic and organic liquids may be converted into liquid marbles. Liquid marbles demonstrate elastic properties and do not coalesce when bounced or pressed lightly. Liquid marbles demonstrate a potential as micro-reactors, micro-containers for growing micro-organisms and cells, micro-fluidics devices, and have even been used in unconventional computing. Liquid marbles remain stable on solid and liquid surfaces. Statics and dynamics of rolling and bouncing of liquid marbles were reported. Liquid marbles coated with poly-disperse and mono-disperse particles have been reported. Liquid marbles are not hermetically coated by solid particles but connected to the gaseous phase. Kinetics of the evaporation of liquid marbles has been investigated.

References

  1. ↑ Cheung, C. L.; Nikolic, R. J.; Reinhardt, C. E.; Wang, T. F. (2006). "Fabrication of nanopillars by nanosphere lithography". Nanotechnology. 17 (5): 1339–1343. Bibcode:2006Nanot..17.1339C. doi:10.1088/0957-4484/17/5/028. S2CID   8690053.
  2. 1 2 Jang, Dongjin; Kim, Younghoon; Kim, Tae Yun; Koh, Kunsuk; Jeong, Unyong; Cho, Jinhan (2016). "Force-assembled triboelectric nanogenerator with high-humidity-resistant electricity generation using hierarchical surface morphology". Nano Energy. 20: 283–293. doi:10.1016/j.nanoen.2015.12.021.
  3. 1 2 3 4 Colson, Pierre; Henrist, Catherine; Cloots, Rudi (2013). "Nanosphere Lithography: A Powerful Method for the Controlled Manufacturing of Nanomaterials". Journal of Nanomaterials. 2013: 1–19. doi: 10.1155/2013/948510 . ISSN   1687-4110.
  4. ↑ C. Zhang, et al. Fabricating Ordered 2-D Nano-Structured Arrays Using Nanosphere Lithography. MethodsX 4, 2017, pp. 229-242. DOI:10.1016/j.mex. open access
  5. 1 2 Sirotkin, Evgeny; Apweiler, Julius D.; Ogrin, Feodor Y. (2010-07-06). "Macroscopic Ordering of Polystyrene Carboxylate-Modified Nanospheres Self-Assembled at the Water−Air Interface". Langmuir. 26 (13): 10677–10683. doi:10.1021/la1009658. hdl: 10871/12027 . ISSN   0743-7463. PMID   20423068.
  6. ↑ Hatzor-de Picciotto, A.; Wissner-Gross, A. D.; Lavallee, G.; Weiss, P. S. (2007). "Arrays of Cu(2+)-complexed organic clusters grown on gold nano dots" (PDF). Journal of Experimental Nanoscience. 2 (1–2): 3–11. Bibcode:2007JENan...2....3P. doi:10.1080/17458080600925807. S2CID   55435913.
  7. ↑ Ching-Mei Hsu, Stephen T. Connor, Mary X. Tang, and Yi Cui (2008). "Wafer-scale silicon nanopillars and nanocones by Langmuir–Blodgett assembly and etching". Applied Physics Letters. 93 (13): 133109. Bibcode:2008ApPhL..93m3109H. doi:10.1063/1.2988893. S2CID   123191151.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  8. ↑ Arno Knapitsch, Etiennette Auffray, George Barbastathis, Celine Chevalier, Chih-Hung Hsieh, Jeong-Gil Kim, Shuai Li, Matthew S. J. Marshall, Radoslaw Mazurczyk, Pawel Modrzynski, Vivek Nagarkar, Ioannis Papakonstantinou, Bipin Singh, Alaric Taylor, Paul Lecoq (2016). "Large scale production of photonic crystals on scintillators" (PDF). IEEE Transactions on Nuclear Science. 63 (2): 639. Bibcode:2016ITNS...63..639K. doi:10.1109/TNS.2016.2535328. S2CID   20935417.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. ↑ Liu, Jing; Chen, Chaoyang; Yang, Guangsong; Chen, Yushan; Yang, Cheng-Fu (2017-04-03). "Effect of the Fabrication Parameters of the Nanosphere Lithography Method on the Properties of the Deposited Au-Ag Nanoparticle Arrays". Materials. 10 (4): 381. Bibcode:2017Mate...10..381L. doi: 10.3390/ma10040381 . PMC   5506964 . PMID   28772741.
  10. ↑ Mikac, Lara; Ivanda, Mile; Gotić, Marijan; Janicki, Vesna; Zorc, Hrvoje; Janči, Tibor; Vidaček, Sanja (2017-10-15). "Surface-enhanced Raman spectroscopy substrate based on Ag-coated self-assembled polystyrene spheres". Journal of Molecular Structure. 1146: 530–535. Bibcode:2017JMoSt1146..530M. doi:10.1016/j.molstruc.2017.06.016. ISSN   0022-2860.
  11. ↑ Oliveira, Rui D.; Mouquinho, Ana; Centeno, Pedro; Alexandre, Miguel; Haque, Sirazul; Martins, Rodrigo; Fortunato, Elvira; Águas, Hugo; Mendes, Manuel J. (2021). "Colloidal Lithography for Photovoltaics: An Attractive Route for Light Management". Nanomaterials. 11 (7): 1665. doi: 10.3390/nano11071665 . ISSN   2079-4991. PMC   8307338 . PMID   34202858.
  12. ↑ Oliveira, Rui D.; Mouquinho, Ana; Centeno, Pedro; Alexandre, Miguel; Haque, Sirazul; Martins, Rodrigo; Fortunato, Elvira; Águas, Hugo; Mendes, Manuel J. (2021). "Colloidal Lithography for Photovoltaics: An Attractive Route for Light Management". Nanomaterials. 11 (7): 1665. doi: 10.3390/nano11071665 . ISSN   2079-4991. PMC   8307338 . PMID   34202858.
  13. 1 2 Boane, Jenny L. N.; Centeno, Pedro; Mouquinho, Ana; Alexandre, Miguel; Calmeiro, Tomás; Fortunato, Elvira; Martins, Rodrigo; Mendes, Manuel J.; Águas, Hugo (2021). "Soft-Microstructured Transparent Electrodes for Photonic-Enhanced Flexible Solar Cells". Micro. 1 (2): 215–227. doi: 10.3390/micro1020016 . hdl: 10362/135394 . ISSN   2673-8023. Creative Commons by small.svg  This article incorporates textfrom this source, which is available under the CC BY 4.0 license.
  14. ↑ Sanchez-Sobrado, Olalla; Mendes, Manuel J.; Mateus, Tiago; Costa, João; Nunes, Daniela; Aguas, Hugo; Fortunato, Elvira; Martins, Rodrigo (2020-01-15). "Photonic-structured TCO front contacts yielding optical and electrically enhanced thin-film solar cells". Solar Energy. 196: 92–98. Bibcode:2020SoEn..196...92S. doi: 10.1016/j.solener.2019.11.051 . hdl: 10362/92793 . ISSN   0038-092X. S2CID   212424973.
  15. ↑ Centeno, Pedro; Alexandre, Miguel F.; Chapa, Manuel; Pinto, Joana V.; Deuermeier, Jonas; Mateus, Tiago; Fortunato, Elvira; Martins, Rodrigo; Águas, Hugo; Mendes, Manuel J. (2020). "Self‐Cleaned Photonic‐Enhanced Solar Cells with Nanostructured Parylene‐C". Advanced Materials Interfaces. 7 (15): 2000264. doi:10.1002/admi.202000264. hdl: 10362/118625 . ISSN   2196-7350. S2CID   219030487.
  16. ↑ Schuster, Christian Stefano; Crupi, Isodiana; Halme, Janne; Koç, Mehmet; Mendes, Manuel João; Peters, Ian Marius; Yerci, Selçuk (2022), Lackner, Maximilian; Sajjadi, Baharak; Chen, Wei-Yin (eds.), "Empowering Photovoltaics with Smart Light Management Technologies", Handbook of Climate Change Mitigation and Adaptation, Cham: Springer International Publishing, pp. 1165–1248, doi:10.1007/978-3-030-72579-2_112, ISBN   978-3-030-72579-2 , retrieved 2023-03-19
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.