Posts belonging to Category Nanolithography



Smart Paper Conducts Electricity, Detects Water

In cities and large-scale manufacturing plants, a water leak in a complicated network of pipes can take tremendous time and effort to detect, as technicians must disassemble many pieces to locate the problem. The American Water Works Association indicates that nearly a quarter-million water line breaks occur each year in the U.S., costing public water utilities about $2.8 billion annually.

A University of Washington (UW) team wants to simplify the process for discovering detrimental leaks by developing “smartpaper that can sense the presence of water. The paper, laced with conductive nanomaterials, can be employed as a switch, turning on or off an LED light or an alarm system indicating the absence or presence of water.

Water sensing is very challenging to do due to the polar nature of water, and what is used now is very expensive and not practical to implement,” said lead author Anthony Dichiara, a UW assistant professor of bioresource science and engineering in the School of Environment and Forest Sciences. “That led to the reason to pursue this work.”

Along with Dichiara, a team of UW undergraduate students in the Bioresource Science and Engineering program successfully embedded nanomaterials in paper that can conduct electricity and sense the presence of water. Starting with pulp, they manipulated the wood fibers and carefully mixed in nanomaterials using a standard process for papermaking, but never before used to make sensing papers.

Discovering that the paper could detect the presence of water came by way of a fortuitous accident. Water droplets fell onto the conductive paper the team had created, causing the LED light indicating conductivity to turn off. Though at first they thought they had ruined the paper, the researchers realized they had instead created a paper that was sensitive to water.
The researchers described their discovery in a paper appearing in the Journal of Materials Chemistry A.

Source: http://www.washington.edu/

Nanoscale Memory Cell

Developing a superconducting computer that would perform computations at high speed without heat dissipation has been the goal of several research and development initiatives since the 1950s. Such a computer would require a fraction of the energy current supercomputers consume, and would be many times faster and more powerful. Despite promising advances in this direction over the last 65 years, substantial obstacles remain, including in developing miniaturized low-dissipation memory.

Researchers at the University of Illinois at Urbana-Champaign have developed a new nanoscale memory cell that holds tremendous promise for successful integration with superconducting processors. The new technology, created by Professor of Physics Alexey Bezryadin and graduate student Andrew Murphy, in collaboration with Dmitri Averin, a professor of theoretical physics at State University of New York at Stony Brook, provides stable memory at a smaller size than other proposed memory devices.

The device comprises two superconducting nanowires, attached to two unevenly spaced electrodes that were “written” using electron-beam lithography. The nanowires and electrodes form an asymmetric, closed superconducting loop, called a nanowire ‘SQUID’ (superconducting quantum interference device). The direction of current flowing through the loop, either clockwise or counterclockwise, equates to the “0” or “1” of binary code.

This is very exciting. Such superconducting memory cells can be scaled down in size to the range of few tens of nanometers, and are not subject to the same performance issues as other proposed solutions,” comments Bezryadin.

Murphy adds, “Other efforts to create a scaled-down superconducting memory cell weren’t able to reach the scale we have. A superconducting memory device needs to be cheaper to manufacture than standard memory now, and it needs to be dense, small, and fast.”

Source: https://physics.illinois.edu/

30 Billion Switches Onto The New IBM Nano-based Chip

IBM is clearly not buying into the idea that Moore’s Law is dead after it unveiled a tiny new transistor that could revolutionise the design, and size, of future devices. Along with Samsung and Globalfoundries, the tech firm has created a ‘breakthrough’ semiconducting unit made using stacks of nanosheets. The companies say they intend to use the transistors on new five nanometer (nm) chips that feature 30 billion switches on an area the size of a fingernail. When fully developed, the new chip will help with artificial intelligence, the Internet of Things, and cloud computing.

For business and society to meet the demands of cognitive and cloud computing in the coming years, advancement in semiconductor technology is essential,” said Arvind Krishna, senior vice president, Hybrid Cloud, and director, IBM Research.

IBM has been developing nanometer sheets for the past 10 years and combined stacks of these tiny sheets using a process called Extreme Ultraviolet (EUV) lithography to build the structure of the transistor.

Using EUV lithography, the width of the nanosheets can be adjusted continuously, all within a single manufacturing process or chip design,” IBM and the other firms said. This allows the transistors to be adjusted for the specific circuits they are to be used in.

Source: http://www.wired.co.uk/

Efficient, Fast, Large-scale 3-D Manufacturing

Washington State University (WSU) researchers have developed a unique, 3-D manufacturing method that for the first time rapidly creates and precisely controls a material’s architecture from the nanoscale to centimeters – with results that closely mimic the intricate architecture of natural materials like wood and bone.

3D manufacturing Hex-Scaffold-web-

This is a groundbreaking advance in the 3-D architecturing of materials at nano- to macroscales with applications in batteries, lightweight ultrastrong materials, catalytic converters, supercapacitors and biological scaffolds,” said Rahul Panat, associate professor in the School of Mechanical and Materials Engineering, who led the research. “This technique can fill a lot of critical gaps for the realization of these technologies.”

The WSU research team used a 3-D printing method to create foglike microdroplets that contain nanoparticles of silver and to deposit them at specific locations. As the liquid in the fog evaporated, the nanoparticles remained, creating delicate structures. The tiny structures, which look similar to Tinkertoy constructions, are porous, have an extremely large surface area and are very strong.

The researchers would like to use such nanoscale and porous metal structures for a number of industrial applications; for instance, the team is developing finely detailed, porous anodes and cathodes for batteries rather than the solid structures that are now used. This advance could transform the industry by significantly increasing battery speed and capacity and allowing the use of new and higher energy materials.

They report on their work in the journal  Science Advances  and have filed for a patent.

Source: https://news.wsu.edu/

Microscope’s Electron Beam Writes Data Onto A Hard Disk

Every day we upload over a billion photos to the Internet. Even when photos are online they are generally stored on computer hard disk drives, but these drives have limited lifetimes.

electron_beam_welding_flare-1000px

How are we going to be able to store all that information and know that we can leave it there effectively in perpetuity and recall it in 50 years time, in 500 years time? Those are big challenges“, says Porfessor Simon Ringer,  from the Faculty of engineering and information technologies, University of Sydney (Australia). A young PhD student at the University is rising to that challenge. Zibin Chen was examining ferroelectric materials under an electron microscope. He wanted to know if any could be used for data storage, when he made a chance discovery. He noticed the electron beam of the microscope could actually write data onto a disk.

When we discovered this phenomenon we were so excited about it, because we think this is the first time ever in the world to find that the electron beam can actually write very small information on this material“, adds Zibin chen Ph.D candidate at the Faculty of engineering and information technologies, University of Sydney.

The conventional hard disk drive found in most personal computers stores our photos, videos and music as a stream of zeros and ones on a magnetic surface. But hard disk drives are prone to failure, and if they get bumped, the head will scratch the platter, and the data is lost. The University of Sydney‘s system uses an electron beam to write on ceramic material. There are no moving parts, so little risk of scratching. Still in the laboratory stage, the team expects the first use of this technology will be to help store photos and documents in the Cloud. It currently stores 10 times the amount of data as a conventional hard drive, but Chen’s supervisor is confident they can take it much further.

What we’ve done here at the University of Sydney is a breakthrough that has a roadmap of a 100 times change in the computer memory capacity“, comments Professor Ringer.  As the number of photos taken each day keeps growing, Chen’s chance discovery could offer a new way to store our precious memories for generations to come.

Source: http://www.reuters.com/

Solar Cells: How To Transform More Solar Energy Into Electricity

Sagrario Domínguez-Fernández, a Spanish telecommunications engineer at CEMITEC, has managed to increase light absorption in silicon by means of nanostructures etched onto photovoltaic cells. This increases the efficiency obtained in these electronic devices which are made of this element and which transform solar energy into electricity.
solar cells

Over 30 percent of the sunlight that strikes a silicon is reflected, which means it cannot be used in the photoelectric conversion,” explained Sagrario Domínguez. “Because the nanostructures on the surface of a material have dimensions in the light wavelength range, they interfere with the surface in a particular way and allow the amount of reflected light to be modified.”

Sagrario Domínguez designed and optimised structures on a nanometric scaleto try and find one that would minimise the reflectance [ability of a surface to reflect light] of the silicon in the wavelength range in which solar cells function.” In their manufacturing process, she resorted to what is known as laser interference lithography which consists of applying laser radiation to a photo-sensitive material to create structures on a nanometric scale. Specifically, she used polished silicon wafers to which she gave the shape of cylindrical pillar and obtained a 77 percent reduction in the reflectance of this element.

Sagrario Domínguez then went on to modify the manufacturing processes to produce the nanostructures on the silicon substrates used in commercial solar cells. “These substrates have dimensions and a surface roughness that makes them, ‘a priori’, unsuitable for processes,” pointed out the researcher. Having overcome the difficulties, she incorporated nanostructures onto following the standard processes of the photovoltaics industry. “According to the literature, this is the first time that it has been possible to manufacture periodic nanostructures; they are the ones that on the surface of a material are continuously repeated on substrates of this type, and therefore, the first standard solar cell with periodic nanostructures,” pointed out the new MIT PhD holder. The efficiency obtained is 15.56 percent, which is a very promising value when compared with others included in the literature.

Source: http://phys.org/

Smart Glass

Most smartphones have a slick, sizable piece of glass on their face. But the glass itself is notsmart” — the intelligent components lie beneath. That could soon change, thanks to researchers at the University of Adelaide in Australia who have lent “smart potential” to glass. They’ve done so by embedding light-emitting nanoparticles within the glass without affecting the glass’s physical properties — its transparency and malleability, for example.

This method for embedding light-emitting nanoparticles into glass without losing any of their unique properties – a major step towards ‘smart glass’ applications such as 3D display screens or remote radiation sensors.

The new “hybrid glass” successfully combines the properties of these special luminescent (or light-emitting) nanoparticles with the well-known aspects of glass, such as transparency and the ability to be processed into various shapes including very fine optical fibres.

smart glass2An illustration shows light-emitting nanoparticles embedded in glass

These novel luminescent nanoparticles, called upconversion nanoparticles, have become promising candidates for a whole variety of ultra-high tech applications such as biological sensing, biomedical imaging and 3D volumetric displays,” says lead author Dr Tim Zhao, from the University of Adelaide’s School of Physical Sciences and Institute for Photonics and Advanced Sensing (IPAS).

Integrating these nanoparticles into glass, which is usually inert, opens up exciting possibilities for new hybrid materials and devices that can take advantage of the properties of nanoparticles in ways we haven’t been able to do before. For example, neuroscientists currently use dye injected into the brain and lasers to be able to guide a glass pipette to the site they are interested in. If fluorescent nanoparticles were embedded in the glass pipettes, the unique luminescence of the hybrid glass could act like a torch to guide the pipette directly to the individual neurons of interest”, adds Dr Zhao.

The research, in collaboration with Macquarie University and University of Melbourne, has been published online in the journal Advanced Optical Materials.

Source: https://www.adelaide.edu.au/

Do-It-Yourself Technique To Produce Flat Optics

Researchers from the University of Illinois at Urbana-Champaign have developed a simplified approach to fabricating flat, ultrathin optics. The new approach enables simple etching without the use of acids or hazardous chemical etching agents.

Do It Yourself Flat opticsExperimentally obtained image of a Fresnel zone plate (left) for focusing light that is fabricated with plasmon-assisted etching. A two-dimensional array of pillar-supported bowtie nanoantennas [zoomed in image (right)] comprises this flat lens

Our method brings us closer to making do-it-yourself optics a reality by greatly simplifying the design iteration steps,” explained Kimani Toussaint, an associate professor of mechanical science and engineering who led the research published in Nature Communications. “The process incorporates a nanostructured template that can be used to create many different types of optical components without the need to go into a cleanroom to make a new template each time a new optical component is neededIn recent years, the push to foster increased technological innovation and basic scientific and engineering interest from the broadest sectors of society has helped to accelerate the development of do-it-yourself (DIY) components, particularly those related to low-cost microcontroller boards,” Toussaint remarked.
Simplifying and reducing the steps between a basic design and fabrication is the primary attraction of DIY kits, but typically at the expense of quality. We present plasmon-assisted etching as an approach to extend the DIY theme to optics with only a modest tradeoff in quality, specifically, the table-top fabrication of planar optical components.

Our method uses the intuitive design aspects of diffractive optics by way of simple surface modification, and the electric-field enhancement properties of metal nanoantennas, which are typically the building blocks of metasurfaces,” stated Hao Chen, a former postdoctoral researcher in Toussaint’s lab and first author of the paper, “Towards do-it-yourself planar optical components using plasmon-assisted etching.

Source: http://engineering.illinois.edu/

Bubble-Pen To Build Nanocomputer, Sensor, Solar Panel…

Researchers in the Cockrell School of Engineering at The University of Texas at Austin have solved a problem in micro- and nanofabrication — how to quickly, gently and precisely handle tiny particles — that will allow researchers to more easily build tiny machines, biomedical sensors, optical computers, solar panels and other devices. They have developed a device and technique, called bubble-pen lithography, that can efficiently handle nanoparticles — the tiny pieces of gold, silicon and other materials used in nanomanufacturing. The new method relies on microbubbles to inscribe, or write, nanoparticles onto a surface.

A research team led by Texas Engineering assistant professor Yuebing Zheng has invented a way to handle these small particles and lock them into position without damaging them. Using microbubbles to gently transport the particles, the bubble-pen lithography technique can quickly arrange particles in various shapes, sizes, compositions and distances between nanostructures.

bubble-pen litho

The ability to control a single nanoparticle and fix it to a substrate without damaging it could open up great opportunities for the creation of new materials and devices,” Zheng said. “The capability of arranging the particles will help to advance a class of new materials, known as metamaterials, with properties and functions that do not exist in current natural materials.

The team, which includes Cockrell School associate professor Deji Akinwande and professor Andrew Dunn, describe their patented device and technique in a paper published in Nano Letters.

Source: https://news.utexas.edu/

Printing With Nanomaterials

Researchers at Binghamton University are focusing on printed electronics: using inkjet technology to print electronic nanomaterials onto flexible substrates. When compared to traditional methods used in microelectronics fabrication, the new technology conserves material and is more environmentally friendly.

Think of inkjet printing and you’ll likely picture an old printer in an office. Not so if you’re Timothy Singler, director of graduate studies and professor of mechanical engineering at Binghamton University. In the Transport Sciences Core at the Innovative Technologies Complex, Singler is collaborating with Paul Chiarot and Frank Yong, assistant professors of mechanical engineering, to study inkjet printing of functional materials.

Functional materials are categorized in terms of the actions they can perform rather than on the basis of their origins. Solution-processed materials may have electrical, optical, chemical, magnetic, thermal or other functionalities. For example, silver is strongly electrically conductive and can be formulated into nanoparticle ink. However, Singler explains that printing with solution-processed nanomaterials instead of traditional inks is significantly more complex.

3D printing “One really has to study how nanomaterials deposit on a substrate — what structures they form, how you can control them — because you’re dispersing the nanomaterials into a liquid so you can print them, and that liquid volatilizes, leaving only the material on the substrate. But the evaporation process and capillarity cause very complex flows that transport the material you’re trying to deposit in nonintuitive ways,” Singler says. “These flows have to be controlled to achieve an optimal functional structure at the end.”

Source: http://www.binghamton.edu/

Solar Film: How To Increase The Absorption Of Sunlight

A biological structure in mammalian eyes has inspired a team headed by Silke Christiansen to design an inorganic counterpart for use in solar cells. With the help of conventional semiconductor processes, they etched micron-sized vertical funnels shoulder-to-shoulder in a silicon substrate. Using mathematical models and experiments, they tested how these kind of funnel arrays collect incident light and conduct it to the active layer of a silicon solar cell. Their result: this arrangement of funnels increases photo absorption by about 65% in a thin-film solar cell fitted with such an array and is reflected in considerably increased solar cell efficiency, among other improved parameters. This closely packed arrangement of cones has now inspired the team headed by Prof. Silke Christiansen to replicate something similar in silicon as a surface for solar cells and investigate its suitability for collecting and conducting light. Christiansen heads the Institute for Nanoarchitectures for Energy Conversion at the Helmholtz-Zentrum Berlin (HZB) and a research team at the Max Planck Institute for the Science of Light (MPL) – Germany..

solar funnelThe simulation shows how the concentration of light (red = high concentration, yellow= low concentration) rises in the funnels with declining diameter of the lower end of the funnel
We’ve shown in this work that the light funnels absorbs considerably more light than other optical architectures tested over the last while”, says Sebastian Schmitt, one of the two first authors of the publication that has appeared in journal Nature Scientific Reports.

Source: http://www.helmholtz-berlin.de/

NanoRobots Manufacture Devices At NanoScale

What does it take to fabricate electronic and medical devices tinier than a fraction of a human hair? Nanoengineers at the University of California, San Diego recently invented a new method of lithography in which nanoscale robots swim over the surface of light-sensitive material to create complex surface patterns that form the sensors and electronics components on nanoscale devices. Their research, published recently in the journal Nature Communications, offers a simpler and more affordable alternative to the high cost and complexity of current state-of-the-art nanofabrication methods such as electron beam writing.
Led by distinguished nanoengineering professor and chair Joseph Wang, the team developed nanorobots, or nanomotors, that are chemically-powered, self-propelled and magnetically controlled. Their proof-of-concept study demonstrates the first nanorobot swimmers able to manipulate light for nanoscale surface patterning. The new strategy combines controlled movement with unique light-focusing or light-blocking abilities of nanoscale robots.

nanorobotNanoengineers have invented a spherical nanorobot made of silica that focuses light like a near-field lens to write surface patterns for nanoscale devices. In this image, the red and purple areas indicate where the light is being magnified to produce a trench pattern on light-sensitive material

All we need is these self-propelled nanorobots and UV light,” said Jinxing Li, a doctoral student at the Jacobs School of Engineering and first author. “They work together like minions, moving and writing and are easily controlled by a simple magnet.

Source: http://www.jacobsschool.ucsd.edu/