But our expectation that the next shopping season will inevitably offer an upgrade to more-powerful gadgets largely depends on size – namely, the ability of the industry to shrink transistors so that more can fit on ever-tinier chip surfaces.
Nanodots of iron oxide were laid out in a highly ordered pattern without the use of templates. The average diameter of the particles was 25 nanometers, with regular spacing of 45 nm.
Engineers have been up to the task of electronics miniaturization for decades now, and the principle that the computer industry will be able to do it on a regular schedule – as codified in Moore’s Law – won’t come into doubt any time soon, thanks to researchers like the University of South Carolina’s Chuanbing Tang.
Tang is a leader in constructing miniscule structures from the bottom up, rather than the top down. Currently, modern electronics are primarily fabricated by the latter method: the smooth surface of a starting material – say, a wafer of silicon – is etched through micro- or nanolithography to establish a pattern on it. The top-down method might involve a prefabricated template, such as a photomask, to establish the pattern. But the approach is becoming more and more challenging, because reducing the size of the features on the requisite templates is getting extremely expensive as engineers work their way further down the nanoscale. “Going from 500 to sub-30 nanometers is cost prohibitive for large-scale production,” said Tang, an assistant professor in the department of chemistry and biochemistry in USC’s College of Arts and Sciences.
As a chemist, Tang uses a bottom-up approach: he works with the individual molecules that go onto a surface, coaxing them to self-arrange into the patterns needed. One established method of doing this involves block copolymers, in which a polymer chain is made up of two or more sections of different polymerized monomers.
If the different block sections are properly designed, the blocks will self-aggregate when placed on a surface, and the aggregation can be harnessed to create desirable patterns on the nanoscale without the need for any templates. Di-block copolymers of poly(ethylene oxide) and polystyrene, for example, have been used to construct highly ordered arrays of perpendicular cylinders of nanoscale materials. Solvent evaporation, or annealing, of these polymers on surfaces exerts an external directional field that can enhance the patterning process and create nearly defect-free arrays.
Tang’s laboratory just published a paper for the special “Emerging Investigators 2013” issue of the journal Chemical Communications that takes this method to a new level. Working together with graduate student Christopher Hardy, Tang led a team that fabricated nanoparticles of pure, crystalline iron oxide with controlled size and spacing on silicon wafers by covalently incorporating a ferrocene moiety into a tri-block copolymer.
Incorporating metals into nanoscale designs is crucial for fabricating electronic devices, and Tang’s method is a step forward for the field. Because ferrocene is covalently bonded to the block copolymer, there is no need for a complexation step to add a metal-containing compound to the surface – a burdensome requirement of most previous methods. Moreover, their technique is a step beyond related polymer systems that contain covalent ferrocenylsilane linkages, in which removal of the organic components leaves behind silicon oxide as an impurity in the metal oxide.
The technique is a promising addition to the available tools for addressing the chronic need to decrease the size of electronic components. “The industry won’t replace top-down methods,” Tang said, “but they plan to use bottom-up together with the existing top-down methods soon.”
There’s versatility in the technique as well. “Here we use a ferrocene-containing polymer, which we convert into the inorganic iron oxide. But if we replace the ferrocene in the polymer with carbon precursor, we could make a perpendicular carbon nanorod, which would have a lot of potential uses,” Tang said. “Or we can incorporate a semi-conducting polymer, like polythiophene, which would be very useful in solar cell applications.”
The work was supported by Semiconductor Research Corporation (Task ID 2222.001) and National Science Foundation (CHE-1151479).
Steven Powell | Newswise
Link Discovered between Immune System, Brain Structure and Memory
26.04.2017 | Universität Basel
Researchers develop eco-friendly, 4-in-1 catalyst
25.04.2017 | Brown University
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
26.04.2017 | Materials Sciences
26.04.2017 | Agricultural and Forestry Science
26.04.2017 | Physics and Astronomy