tag:theconversation.com,2011:/us/topics/transistors-22658/articlesTransistors – The Conversation2023-12-18T16:17:12Ztag:theconversation.com,2011:article/2200442023-12-18T16:17:12Z2023-12-18T16:17:12ZA new supercomputer aims to closely mimic the human brain — it could help unlock the secrets of the mind and advance AI<figure><img src="https://images.theconversation.com/files/566252/original/file-20231218-15-hajmbj.jpg?ixlib=rb-1.1.0&rect=19%2C9%2C6470%2C3940&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/businessman-touching-digital-human-brain-cell-582507070">Sdecoret / Shutterstock</a></span></figcaption></figure><p>A supercomputer scheduled to go online in April 2024 will rival the estimated rate of operations in the human brain, <a href="https://www.westernsydney.edu.au/newscentre/news_centre/more_news_stories/world_first_supercomputer_capable_of_brain-scale_simulation_being_built_at_western_sydney_university">according to researchers in Australia</a>. The machine, called DeepSouth, is capable of performing 228 trillion operations per second. </p>
<p>It’s the world’s first supercomputer capable of simulating networks of neurons and synapses (key biological structures that make up our nervous system) at the scale of the human brain.</p>
<p>DeepSouth belongs to an approach <a href="https://www.nature.com/articles/s43588-021-00184-y">known as neuromorphic computing</a>, which aims to mimic the biological processes of the human brain. It will be run from the International Centre for Neuromorphic Systems at Western Sydney University.</p>
<p>Our brain is the most amazing computing machine we know. By distributing its
computing power to billions of small units (neurons) that interact through trillions of connections (synapses), the brain can rival the most powerful supercomputers in the world, while requiring only the same power used by a fridge lamp bulb.</p>
<p>Supercomputers, meanwhile, generally take up lots of space and need large amounts of electrical power to run. The world’s most powerful supercomputer, the <a href="https://www.hpe.com/uk/en/compute/hpc/cray/oak-ridge-national-laboratory.html">Hewlett Packard Enterprise Frontier</a>, can perform just over one quintillion operations per second. It covers 680 square metres (7,300 sq ft) and requires 22.7 megawatts (MW) to run. </p>
<p>Our brains can perform the same number of operations per second with just 20 watts of power, while weighing just 1.3kg-1.4kg. Among other things, neuromorphic computing aims to unlock the secrets of this amazing efficiency.</p>
<h2>Transistors at the limits</h2>
<p>On June 30 1945, the mathematician and physicist <a href="https://www.ias.edu/von-neumann">John von Neumann</a> described the design of a new machine, the <a href="https://ieeexplore.ieee.org/document/194089">Electronic Discrete Variable Automatic Computer (Edvac)</a>. This effectively defined the modern electronic computer as we know it. </p>
<p>My smartphone, the laptop I am using to write this article and the most powerful supercomputer in the world all share the same fundamental structure introduced by von Neumann almost 80 years ago. <a href="https://www.sciencedirect.com/topics/computer-science/von-neumann-architecture">These all have distinct processing and memory units</a>, where data and instructions are stored in the memory and computed by a processor.</p>
<p>For decades, the number of transistors on a microchip doubled approximately every two years, <a href="https://ieeexplore.ieee.org/abstract/document/591665">an observation known as Moore’s Law</a>. This allowed us to have smaller and cheaper computers. </p>
<p>However, transistor sizes are now approaching the atomic scale. At these tiny sizes, excessive heat generation is a problem, as is a phenomenon called quantum tunnelling, which interferes with the functioning of the transistors. <a href="https://qz.com/852770/theres-a-limit-to-how-small-we-can-make-transistors-but-the-solution-is-photonic-chips#:%7E:text=They're%20made%20of%20silicon,we%20can%20make%20a%20transistor.">This is slowing down</a> and will eventually halt transistor miniaturisation.</p>
<p>To overcome this issue, scientists are exploring new approaches to
computing, starting from the powerful computer we all have hidden in our heads, the human brain. Our brains do not work according to John von Neumann’s model of the computer. They don’t have separate computing and memory areas. </p>
<p>They instead work by connecting billions of nerve cells that communicate information in the form of electrical impulses. Information can be passed from <a href="https://qbi.uq.edu.au/brain-basics/brain/brain-physiology/action-potentials-and-synapses">one neuron to the next through a junction called a synapse</a>. The organisation of neurons and synapses in the brain is flexible, scalable and efficient. </p>
<p>So in the brain – and unlike in a computer – memory and computation are governed by the same neurons and synapses. Since the late 1980s, scientists have been studying this model with the intention of importing it to computing.</p>
<figure class="align-center ">
<img alt="Microchip." src="https://images.theconversation.com/files/566265/original/file-20231218-25-yjbwxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566265/original/file-20231218-25-yjbwxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566265/original/file-20231218-25-yjbwxy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566265/original/file-20231218-25-yjbwxy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566265/original/file-20231218-25-yjbwxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566265/original/file-20231218-25-yjbwxy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566265/original/file-20231218-25-yjbwxy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The continuing miniaturisation of transistors on microchips is limited by the laws of physics.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/close-presentation-new-generation-microchip-gloved-691548583">Gorodenkoff / Shutterstock</a></span>
</figcaption>
</figure>
<h2>Imitation of life</h2>
<p>Neuromorphic computers are based on intricate networks of simple, elementary processors (which act like the brain’s neurons and synapses). The main advantage of this is that these machines <a href="https://www.electronicsworld.co.uk/advances-in-parallel-processing-with-neuromorphic-analogue-chip-implementations/34337/">are inherently “parallel”</a>. </p>
<p>This means that, <a href="https://www.pnas.org/doi/full/10.1073/pnas.95.3.933">as with neurons and synapses</a>, virtually all the processors in a computer can potentially be operating simultaneously, communicating in tandem.</p>
<p>In addition, because the computations performed by individual neurons and synapses are very simple compared with traditional computers, the energy consumption is orders of magnitude smaller. Although neurons are sometimes thought of as processing units, and synapses as memory units, they contribute to both processing and storage. In other words, data is already located where the computation requires it.</p>
<p>This speeds up the brain’s computing in general because there is no separation between memory and processor, which in classical (von Neumann) machines causes a slowdown. But it also avoids the need to perform a specific task of accessing data from a main memory component, as happens in conventional computing systems and consumes a considerable amount of energy. </p>
<p>The principles we have just described are the main inspiration for DeepSouth. This is not the only neuromorphic system currently active. It is worth mentioning the <a href="https://www.humanbrainproject.eu">Human Brain Project (HBP)</a>, funded under an <a href="https://ec.europa.eu/futurium/en/content/fet-flagships.html">EU initiative</a>. The HBP was operational from 2013 to 2023, and led to BrainScaleS, a machine located in Heidelberg, in Germany, that emulates the way that neurons and synapses work. </p>
<p><a href="https://www.humanbrainproject.eu/en/science-development/focus-areas/neuromorphic-computing/hardware/">BrainScaleS</a> can simulate the way that neurons “spike”, the way that an electrical impulse travels along a neuron in our brains. This would make BrainScaleS an ideal candidate to investigate the mechanics of cognitive processes and, in future, mechanisms underlying serious neurological and neurodegenerative diseases.</p>
<p>Because they are engineered to mimic actual brains, neuromorphic computers could be the beginning of a turning point. Offering sustainable and affordable computing power and allowing researchers to evaluate models of neurological systems, they are an ideal platform for a range of applications. They have the potential to both advance our understanding of the brain and offer new approaches to artificial intelligence.</p><img src="https://counter.theconversation.com/content/220044/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Domenico Vicinanza does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Neuromorphic computers aim to one day replicate the amazing efficiency of the brain.Domenico Vicinanza, Associate Professor of Intelligent Systems and Data Science, Anglia Ruskin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2058202023-06-27T12:23:57Z2023-06-27T12:23:57ZThe digital future may rely on ultrafast optical electronics and computers<figure><img src="https://images.theconversation.com/files/532461/original/file-20230616-23761-r0m0kq.jpeg?ixlib=rb-1.1.0&rect=38%2C15%2C1683%2C1239&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The author's lab's ultrafast optical switch in action.</span> <span class="attribution"><span class="source">Mohammed Hassan, University of Arizona</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>If you’ve ever wished you had a faster phone, computer or internet connection, you’ve encountered the personal experience of hitting a limit of technology. But there might be help on the way.</p>
<p>Over the past several decades, scientists and engineers <a href="https://scholar.google.com/citations?user=JA0qsY0AAAAJ&hl=en&oi=ao">like me</a> have worked to develop faster transistors, the electronic components underlying modern electronic and digital communications technologies. These efforts have been based on a category of materials called semiconductors that have special electrical properties. <a href="https://doi.org/10.1038/483S43a">Silicon</a> is perhaps the best known example of this type of material. </p>
<p>But about a decade ago, scientific efforts hit the speed limit of semiconductor-based transistors. Researchers simply can’t make electrons move faster through these materials. One way engineers are trying to address the speed limits inherent in moving a current through silicon is to design shorter physical circuits – essentially giving electrons less distance to travel. Increasing the computing power of a chip comes down to increasing the number of transistors. However, even if researchers are able to get transistors to be very small, they won’t be fast enough for the faster processing and data transfer speeds people and businesses will need.</p>
<p>My <a href="https://hassan.lab.arizona.edu">research group’s work</a> aims to develop faster ways to move data, using ultrafast laser pulses in free space and optical fiber. The laser light travels through optical fiber with almost no loss and with a very low level of noise.</p>
<p>In our most recent study, published in February 2023 in Science Advances, we took a step toward that, demonstrating that it’s possible to use <a href="https://doi.org/10.1126/sciadv.adf1015">laser-based systems</a> equipped with optical transistors, which depend on photons rather than voltage to move electrons, and to transfer information much more quickly than current systems – and do so more effectively than <a href="https://doi.org/10.1038/s41586-021-03866-9">previously reported optical switches</a>.</p>
<h2>Ultrafast optical transistors</h2>
<p>At their most fundamental level, digital transmissions involve a signal switching on and off to represent ones and zeros. Electronic transistors use voltage to send this signal: When the voltage induces the electrons to flow through the system, they signal a 1; when there are no electrons flowing, that signals a 0. This requires a source to emit the electrons and a receiver to detect them. </p>
<p>Our system of ultrafast optical data transmission is based on light rather than voltage. Our research group is one of many working with optical communication at the transistor level – the building blocks of modern processors – to get around the current limitations with silicon. </p>
<p>Our system controls reflected light to transmit information. When light shines on a piece of glass, most of it passes through, though a little bit might reflect. That is what you experience as glare when driving toward sunlight or looking through a window.</p>
<p>We use two laser beams transmitted from two sources passing through the same piece of glass. One beam is constant, but its transmission through the glass is controlled by the second beam. By using the second beam to shift the properties of the glass from transparent to reflective, we can start and stop the transmission of the constant beam, switching the optical signal from on to off and back again very quickly. </p>
<p>With this method, we can switch the glass properties much more quickly than current systems can send electrons. So we can send many more on and off signals – zeros and ones – in less time.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/534180/original/file-20230626-1803-19w9pt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a hand holds a bundle of optical fibers between thumb and first finger" src="https://images.theconversation.com/files/534180/original/file-20230626-1803-19w9pt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/534180/original/file-20230626-1803-19w9pt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=441&fit=crop&dpr=1 600w, https://images.theconversation.com/files/534180/original/file-20230626-1803-19w9pt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=441&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/534180/original/file-20230626-1803-19w9pt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=441&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/534180/original/file-20230626-1803-19w9pt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=554&fit=crop&dpr=1 754w, https://images.theconversation.com/files/534180/original/file-20230626-1803-19w9pt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=554&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/534180/original/file-20230626-1803-19w9pt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=554&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The author’s research group has developed a way to switch light beams on and off, like those passing through these optical fibers, 1 million billion times a second.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/bundle-of-light-wave-cables-fibre-optic-news-photo/976186008">Mediacolors/Construction Photography/Avalon via Getty Images</a></span>
</figcaption>
</figure>
<h2>How fast are we talking?</h2>
<p>Our study took the first step to transmitting data 1 million times faster than if we had used the typical electronics. With electrons, the maximum speed for transmitting data is a <a href="https://www.wolframalpha.com/input?i=nanosecond">nanosecond</a>, one-billionth of a second, which is very fast. But the optical switch we constructed was able to transmit data a million times faster, which took just a few hundred <a href="https://www.wolframalpha.com/input?i=attosecond">attoseconds</a>.</p>
<p>We were also able to transmit those signals securely so that an attacker who tried to intercept or modify the messages would fail or be detected. </p>
<p>Using a laser beam to carry a signal, and adjusting its signal intensity with glass controlled by another laser beam, means the information can travel not only more quickly but also much greater distances. </p>
<p>For instance, the James Webb Space Telescope recently transmitted <a href="https://theconversation.com/james-webb-space-telescope-an-astronomer-explains-the-stunning-newly-released-first-images-186800">stunning images from far out in space</a>. These pictures were transferred as data from the telescope to the base station on Earth at a rate of one “on” or “off” <a href="https://webbtelescope.org/quick-facts">every 35 nanosconds</a> using optical communications.</p>
<p>A laser system like the one we’re developing could speed up the transfer rate a billionfold, allowing faster and clearer exploration of deep space, more quickly revealing the universe’s secrets. And someday computers themselves might run on light.</p><img src="https://counter.theconversation.com/content/205820/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mohammed Hassan receives funding from the Gordon and Betty Moore Foundation and the Air Force Office of Scientific Research.</span></em></p>A researcher explains developments in using light rather than electrons to transmit information securely and quickly, even over long distances.Mohammed Hassan, Associate Professor of Physics and Optical Sciences, University of ArizonaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1466592020-10-05T12:11:28Z2020-10-05T12:11:28ZNeuronlike circuits bring brainlike computers a step closer<figure><img src="https://images.theconversation.com/files/360941/original/file-20200930-16-1uqk1tg.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5991%2C4491&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Brainlike computer chips promise powerful computers that use little energy.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/digital-brain-royalty-free-image/517254617?adppopup=true">D3Damon/E+ via Getty Images</a></span></figcaption></figure><p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take about interesting academic work.</em></p>
<h2>The big idea</h2>
<p>For the first time, my colleagues and <a href="https://scholar.google.com/citations?user=dAFE2L8AAAAJ&hl=en">I</a> have built a single electronic device that is <a href="https://doi.org/10.1038/s41586-020-2735-5">capable of copying the functions of neuron cells</a> in a brain. We then connected 20 of them together to perform a complicated calculation. This work shows that it is scientifically possible to make an advanced computer that does not rely on transistors to calculate and that uses much less electrical power than today’s data centers.</p>
<p>Our research, which I began in 2004, was motivated by two questions. Can we build a single electronic element – the equivalent of a transistor or switch – that performs most of the known functions of neurons in a brain? If so, can we use it as a building block to build useful computers? </p>
<p>Neurons are very finely tuned, and so are electronic elements that emulate them. I co-authored a <a href="https://doi.org/10.1038/nmat3510">research paper</a> in 2013 that laid out in principle what needed to be done. It took my colleague <a href="https://orcid.org/0000-0002-6772-7250">Suhas Kumar</a> and others five years of careful exploration to get exactly the right material composition and structure to produce the necessary property predicted from theory. </p>
<p>Kumar then went a major step further and built a circuit with 20 of these elements connected to one another through a network of devices that can be programmed to have particular capacitances, or abilities to store electric charge. He then mapped a mathematical problem to the capacitances in the network, which allowed him to use the device to find the solution to a small version of a problem that is important in a wide range of modern analytics.</p>
<p>The simple example we used was to look at the possible mutations that have occurred in a family of viruses by comparing pieces of their genetic information.</p>
<h2>Why it matters</h2>
<p>The performance of computers is <a href="https://theconversation.com/with-silicon-pushed-to-its-limits-what-will-power-the-next-electronics-revolution-46287">rapidly reaching a limit</a> because the size of the smallest transistor in integrated circuits is now approaching 20 atoms wide. Any smaller and the physical principles that determine transistor behavior no longer apply. There is a high-stakes competition to see if someone can build a much better transistor, a method for stacking transistors or some other device that can perform the tasks that currently require thousands of transistors. </p>
<p>This quest is important because people have become used to the exponential improvement of computing capacity and efficiency of the past 40 years, and many business models and our economy have been built on this expectation. Engineers and computer scientists have now constructed machines that <a href="https://www.statista.com/statistics/638621/worldwide-data-center-storage-used-by-big-data/">collect enormous amounts of data</a>, which is the ore from which the most valuable commodity, information, is refined. The volume of that data is almost doubling every year, which is outstripping the capability of today’s computers to analyze it. </p>
<h2>What other research is being done in this field</h2>
<p>The fundamental theory of neuron function was first proposed by <a href="https://dx.doi.org/10.1113%2Fjphysiol.2012.230458">Alan Hodgkin and Andrew Huxley</a> about 70 years ago, and it is still in use today. It is very complex and difficult to simulate on a computer, and only recently has it been <a href="https://doi.org/10.1088/0957-4484/24/38/383001">reanalyzed and cast in the mathematics of modern nonlinear dynamics theory</a> by <a href="https://www.eurekalert.org/pub_releases/2020-02/s-loc022520.php">Leon Chua</a>. </p>
<p>I was inspired by this work and have spent much of the past 10 years learning the necessary math and figuring out how to build a real electronic device that works as the theory predicts. </p>
<p>There are numerous research teams around the world taking <a href="https://cacm.acm.org/magazines/2020/8/246356-neuromorphic-chips-take-shape/fulltext">different approaches</a> to building brainlike, or neuromorphic, computer chips.</p>
<h2>What’s next</h2>
<p>The technological challenge now is to scale up our proof-of-principles demonstration to something that can compete against today’s digital behemoths.</p><img src="https://counter.theconversation.com/content/146659/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>R. Stanley Williams was previously employed by Hewlett Packard Enterprise and presently owns stock in the company. He has received research funding from Texas A&M University. He is member of the IEEE.</span></em></p>Artificial brains are far in the future, but computer chips that work like brains could keep computers advancing when today’s silicon transistor chips reach their limit.R. Stanley Williams, Professor of Electrical and Computer Engineering, Texas A&M UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/991562018-07-02T17:47:38Z2018-07-02T17:47:38ZGraphene and the atomic crystals that could see next big breakthrough in tech<figure><img src="https://images.theconversation.com/files/225738/original/file-20180702-116135-1nfm3nz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ready layer one. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/illustration-graphene-molecule-luminous-atoms-crystal-1026845797?src=UWnzYyZVG66GP5lzo-hoig-1-10">tschub</a></span></figcaption></figure><blockquote>
<p>What could we do with layered structures with just the right layers? What would the properties of materials be if we could really arrange the atoms the way we want them?</p>
</blockquote>
<p>The curious American physicist <a href="https://fs.blog/richard-feynman/">Richard Feynman</a> asked these questions in his landmark 1959 lecture, <a href="http://www.phy.pku.edu.cn/%7Eqhcao/resources/class/QM/Feynman%27s-Talk.pdf">There’s Plenty of Room at the Bottom</a>. It bustled with profound ideas about “manipulating and controlling things on the atomic scale”, using quantum mechanics. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/225736/original/file-20180702-116139-52rp50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/225736/original/file-20180702-116139-52rp50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/225736/original/file-20180702-116139-52rp50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=719&fit=crop&dpr=1 600w, https://images.theconversation.com/files/225736/original/file-20180702-116139-52rp50.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=719&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/225736/original/file-20180702-116139-52rp50.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=719&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/225736/original/file-20180702-116139-52rp50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=904&fit=crop&dpr=1 754w, https://images.theconversation.com/files/225736/original/file-20180702-116139-52rp50.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=904&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/225736/original/file-20180702-116139-52rp50.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=904&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Atomic adventurer: Richard Feynman.</span>
<span class="attribution"><a class="source" href="https://it.wikipedia.org/wiki/File:Richard-feynman.jpg#/media/File:Richard-feynman.jpg">Wikimedia</a></span>
</figcaption>
</figure>
<p>Far-fetched at the time, now manipulating layers of atoms is a major research area. To realise Feynman’s vision, researchers at IBM and Bell Labs in the US had to devise a new approach to constructing materials layer by layer: <a href="https://warwick.ac.uk/fac/sci/physics/current/postgraduate/regs/mpagswarwick/ex5/growth/pvd/">molecular beam epitaxy</a> or MBE. </p>
<p>This can be likened to spray painting with atoms. You start by vaporising ultra-pure source materials like gallium, aluminium or indium, and combine them with the likes of arsenic or phosphorus. The vaporised atoms fly through a vacuum chamber towards a base layer made of similar materials. The atoms stick to it and slowly build up a crystal one atomic layer at a time. The ultra-high vacuum ensures impurities are minimal. </p>
<h2>Atomic architects</h2>
<p>While the process is relatively slow – typically only a few atomic layers per minute – the precision is remarkable. It allows technicians to stack different <a href="http://ethw.org/Semiconductors">semiconductor</a> materials on top of each other to create crystals known as <a href="https://theconversation.com/beyond-graphene-scientists-are-creating-an-atomic-lego-set-of-2d-wonder-materials-81709">heterostructures</a>, which can have extremely useful properties. By alternately stacking layers of aluminium arsenide and gallium arsenide, for example, you could produce a material that is extremely good at storing electricity. </p>
<p>Once this technique had been perfected in 1990s and 2000s, scientists were able to control the number of electrons and their energies in a particular crystal. And since light then interacts with these electrons, having more control over electron behaviour means you also gain more control of how they are stimulated by light. </p>
<p>Heterostructures have led to many new discoveries, particularly regarding the quantum behaviour of particles such as electrons within them. Nobel Prizes in Physics have been awarded five separate times (<a href="https://www.nobelprize.org/nobel_prizes/physics/laureates/1973/index.html">1973</a>, <a href="https://www.nobelprize.org/nobel_prizes/physics/laureates/1985/index.html">1985</a>, <a href="https://www.nobelprize.org/nobel_prizes/physics/laureates/1998/">1998</a>, <a href="https://www.nobelprize.org/nobel_prizes/physics/laureates/2000/">2000</a>, and <a href="https://www.nobelprize.org/nobel_prizes/physics/laureates/2014/">2014</a>), and the resulting materials have revolutionised civilisation. </p>
<p>Semiconductor heterostructures enable solar cells, LEDs, lasers and ultra-fast transistors. Even the internet would otherwise be impossible: the lasers which send the light pulses that encode the bits of information online are made from heterostructures, as are the photodetectors that measure these light pulses and decode the information.</p>
<p>There are restrictions, however. The atomic size, spacing and arrangement of these heterostructures cannot be too dissimilar between layers without defects arising. This limits the possible material combinations and the potential to freely engineer the electronic and optical properties. </p>
<p>Also, crystals naturally consist of atoms which form bonds in all three directions. This means there are always unsatisfied atoms with “dangling” bonds at the edges. Foreign impurities seek these bonds and create defects that can destroy other properties. This becomes especially important with smaller crystals, preventing them being integrated to their full extent into modern transistors, lasers and so forth. </p>
<h2>Enter 2D crystals</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/225730/original/file-20180702-116123-e1wmih.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/225730/original/file-20180702-116123-e1wmih.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/225730/original/file-20180702-116123-e1wmih.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=712&fit=crop&dpr=1 600w, https://images.theconversation.com/files/225730/original/file-20180702-116123-e1wmih.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=712&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/225730/original/file-20180702-116123-e1wmih.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=712&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/225730/original/file-20180702-116123-e1wmih.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=895&fit=crop&dpr=1 754w, https://images.theconversation.com/files/225730/original/file-20180702-116123-e1wmih.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=895&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/225730/original/file-20180702-116123-e1wmih.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=895&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Graphene.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/3d-illustration-graphene-material-molecular-grid-761990035?src=xMi-LIYHLvwuYH0jv2AyFQ-1-1">Olive Tree</a></span>
</figcaption>
</figure>
<p>The ultimate in ultra-thin sheets of materials is a single layer of atoms. Fortunately, nature devised such “two-dimensional crystals”. The most famous is <a href="https://theconversation.com/uk/topics/graphene-992">graphene</a>, which is just carbon atoms arranged in a hexagonal pattern. </p>
<p>Graphene is stronger than steel and conducts electricity better than copper. It has many unique and sometimes exotic electronic, optical and mechanical properties – as recognised by the <a href="https://www.nobelprize.org/nobel_prizes/physics/laureates/2010/press.html">Nobel Prize in Physics</a> for its discovery in 2010. </p>
<p>In a perfect graphene crystal, all the atoms are completely bonded to one another and there are no dangling bonds. It is famously possible to produce graphene by peeling apart layers of graphite using scotch tape: graphite is actually many layers of graphene all held together by <a href="https://chem.libretexts.org/Textbook_Maps/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical_Properties_of_Matter/Atomic_and_Molecular_Properties/Intermolecular_Forces/Van_der_Waals_Forces">Van der Waals forces</a>, which are far weaker than the bonds in each constituent sheet of graphene. </p>
<p>Besides graphene, there are many other 2D crystals, each with unique properties. Several occur naturally as gems in the ground, such as molybdnimum disulphide, an important industrial lubricant. Others can be made by molecular beam epitaxy, such as the insulator boron nitride, and crystals in the same family of <a href="https://www.sciencedirect.com/science/article/pii/S1369702116302917">transition metal dichalcogenides</a> as molybdnimum disulphide. </p>
<p>Like graphene is to graphite, scientists “peel off” (or exfoliate) single 2D sheets from larger quantities of these compounds. The inherent thinness of these sheets means they can behave quite differently from the heterostructures described earlier. Different atomically thin materials can be insulating, semiconducting, metallic, magnetic or even superconducting.</p>
<p>Scientists are also able to pick, place and combine these materials at will to form new heterostructures, known as Van der Waals heterostructures, with different properties to the 2D sheets. Crucially, these don’t have the same limitations as their cousins made by molecular beam epitaxy. They can comprise layers of very different atomic crystals, enabling unprecedented and unlimited possibilities for combining different materials.</p>
<p>For example, you can combine magnetic layers with semiconductors and insulators without attracting contaminants like moisture or oxides between layers – impossible with epitaxial heterostructures. This can be used to create devices that control magnetism using electricity, which is the basis for magnetic memory in hard drives. </p>
<p>You can also stack together two identical atomic layers with one turned at an angle. This creates a lattice called a moiré pattern, which provides a new degree of freedom to engineer the electronic and optical properties. The images we are using to demonstrate this at the <a href="https://royalsociety.org/science-events-and-lectures/2018/summer-science-exhibition/exhibits/atomic-architects/">current Royal Society Summer Exhibition</a> in London give a flavour of how this works:</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/225919/original/file-20180703-116126-1b5pgj2.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/225919/original/file-20180703-116126-1b5pgj2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/225919/original/file-20180703-116126-1b5pgj2.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=288&fit=crop&dpr=1 600w, https://images.theconversation.com/files/225919/original/file-20180703-116126-1b5pgj2.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=288&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/225919/original/file-20180703-116126-1b5pgj2.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=288&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/225919/original/file-20180703-116126-1b5pgj2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=362&fit=crop&dpr=1 754w, https://images.theconversation.com/files/225919/original/file-20180703-116126-1b5pgj2.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=362&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/225919/original/file-20180703-116126-1b5pgj2.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=362&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Moire power to your elbow.</span>
<span class="attribution"><span class="source">University of Heriot-Watt</span></span>
</figcaption>
</figure>
<p>While Van der Waals heterostructures are still in their infancy, impressive new physics and capabilities are already emerging. These include smaller, lighter, more flexible and more efficient versions of solar cells, LEDs, transistors and magnetic memory. </p>
<p>In future, we can expect surprises not previously dreamed of. An early example is the <a href="https://www.nature.com/articles/nature26160">recent discovery</a> that when you twist two layers of graphene at a “magic angle” relative to each other, the electrons become superconducting. This breakthrough, not clearly understood yet, could unlock 30-year-old mysteries of how electrons can navigate superconductors without losing any energy. It might allow us to use superconductors at room temperature, with potential benefits for everything from medical imaging and quantum computers to transmitting electricity long distances. </p>
<p>Predicting technological outcomes is not easy, however. As Herbert Kroemer, who shared the Nobel Prize in 2000 for developing semiconductor heterostructures used in high-speed and opto-electronics, <a href="https://www.ece.ucsb.edu/Faculty/Kroemer/pubs/11_03Speculations.pdf">often said</a>: </p>
<blockquote>
<p>The principal applications of any sufficiently new and innovative technology always have been and will continue to be applications created by that technology.</p>
</blockquote><img src="https://counter.theconversation.com/content/99156/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brian Gerardot does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Layering substances like graphene in new ways could help us to build quantum computers or transmit electricity over long distances.Brian Gerardot, Chair in Emerging Technologies, Heriot-Watt UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/689032016-11-29T02:25:35Z2016-11-29T02:25:35ZThe future of electronics is light<figure><img src="https://images.theconversation.com/files/147248/original/image-20161123-19717-hrc3xx.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A basic design of a light-based chip.</span> <span class="attribution"><span class="source">Arnab Hazari</span>, <span class="license">Author provided</span></span></figcaption></figure><p>For the past four decades, the electronics industry has been driven by what is called “<a href="http://www.mooreslaw.org/">Moore’s Law</a>,” which is not a law but more an axiom or observation. Effectively, it suggests that the electronic devices double in speed and capability about every two years. And indeed, every year tech companies come up with new, faster, smarter and better gadgets.</p>
<p>Specifically, Moore’s Law, as articulated by Intel cofounder Gordon Moore, is that “The number of transistors incorporated in a chip will <a href="https://www-ssl.intel.com/content/www/us/en/history/museum-gordon-moore-law.html">approximately double every 24 months</a>.” Transistors, tiny electrical switches, are the fundamental unit that drives all the electronic gadgets we can think of. As they get smaller, they also <a href="http://www.intel.com/content/www/us/en/silicon-innovations/moores-law-technology.html">get faster and consume less electricity</a> to operate.</p>
<p>In the technology world, one of the biggest questions of the 21st century is: How small can we make transistors? If there is a limit to how tiny they can get, we might reach a point at which we can no longer continue to make smaller, more powerful, more efficient devices. It’s an industry with <a href="https://www.statista.com/statistics/272115/revenue-growth-ce-industry/">more than US$200 billion</a> in annual revenue in the U.S. alone. Might it stop growing?</p>
<h2>Getting close to the limit</h2>
<p>At the present, companies like Intel are mass-producing transistors <a href="https://www-ssl.intel.com/content/www/us/en/silicon-innovations/intel-14nm-technology.html">14 nanometers across</a> – just 14 times wider than <a href="https://dx.doi.org/10.1016/0022-2836(81)90099-1">DNA molecules</a>. They’re made of silicon, the <a href="http://hyperphysics.phy-astr.gsu.edu/hbase/Tables/elabund.html">second-most abundant material</a> on our planet. Silicon’s atomic size is <a href="http://www.extremetech.com/computing/97469-is-14nm-the-end-of-the-road-for-silicon-lithography">about 0.2 nanometers</a>.</p>
<p>Today’s transistors are about 70 silicon atoms wide, so the possibility of making them even smaller is itself shrinking. We’re getting very close to the limit of how small we can make a transistor.</p>
<p>At present, transistors use electrical signals – electrons moving from one place to another – to communicate. But if we could use light, made up of photons, instead of electricity, we could make transistors even faster. My work, on finding ways to integrate light-based processing with existing chips, is part of that nascent effort.</p>
<h2>Putting light inside a chip</h2>
<p>A <a href="https://reibot.org/2011/09/06/a-beginners-guide-to-the-mosfet/">transistor has three parts</a>; think of them as parts of a digital camera. First, information comes into the lens, analogous to a transistor’s source. Then it travels through a channel from the image sensor to the wires inside the camera. And lastly, the information is stored on the camera’s memory card, which is called a transistor’s “drain” – where the information ultimately ends up.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/147791/original/image-20161128-22729-tc0olq.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/147791/original/image-20161128-22729-tc0olq.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/147791/original/image-20161128-22729-tc0olq.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=550&fit=crop&dpr=1 600w, https://images.theconversation.com/files/147791/original/image-20161128-22729-tc0olq.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=550&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/147791/original/image-20161128-22729-tc0olq.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=550&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/147791/original/image-20161128-22729-tc0olq.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=691&fit=crop&dpr=1 754w, https://images.theconversation.com/files/147791/original/image-20161128-22729-tc0olq.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=691&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/147791/original/image-20161128-22729-tc0olq.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=691&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Light waves can have different frequencies.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:VisibleEmrWavelengths.svg">maxhurtz</a></span>
</figcaption>
</figure>
<p>Right now, all of that happens by moving electrons around. To substitute light as the medium, we actually need to move photons instead. Subatomic particles like electrons and photons travel in a wave motion, vibrating up and down even as they move in one direction. The length of each wave depends on what it’s traveling through. </p>
<p>In silicon, the most efficient wavelength for photons is <a href="http://www.its.bldrdoc.gov/fs-1037/dir-040/_5927.htm">1.3 micrometers</a>. This is very small – a human hair is <a href="http://www.nano.gov/nanotech-101/what/nano-size">around 100 micrometers across</a>. But <a href="http://homepages.rpi.edu/%7Esawyes/Models_review.pdf">electrons in silicon</a> are even smaller – with wavelengths <a href="http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/debrog2.html">50 to 1,000 times shorter</a> than photons.</p>
<p>This means the equipment to handle photons needs to be bigger than the electron-handling devices we have today. So it might seem like it would force us to build larger transistors, rather than smaller ones.</p>
<p>However, for two reasons, we could keep chips the same size and deliver more processing power, shrink chips while providing the same power, or, potentially both. First, a <a href="http://www.nature.com/lsa/focus/circuits/index.html">photonic chip</a> needs only a few light sources, generating photons that can then be directed around the chip with very small lenses and mirrors.</p>
<p>And second, light is much faster than electrons. On average photons can travel about <a href="http://education.jlab.org/qa/electron_01.html">20 times faster</a> than electrons in a chip. That means computers that are 20 times faster, a speed increase that would take about 15 years to achieve with current technology.</p>
<p>Scientists have demonstrated <a href="http://www.nature.com/lsa/focus/circuits/index.html">progress toward photonic chips</a> in recent years. A key challenge is making sure the new light-based chips can work with all the existing electronic chips. If we’re able to figure out how to do it – or even to use light-based transistors to enhance electronic ones – we could see significant performance improvement.</p>
<h2>When can I get a light-based laptop or smartphone?</h2>
<p>We still have some way to go before the first consumer device reaches the market, and progress takes time. The first transistor was made in the year 1907 using vacuum tubes, which were <a href="http://www.edisontechcenter.org/VacuumTubes.html">typically between one and six inches tall</a> (on average 100 mm). By 1947, the current type of transistor – the one that’s now just 14 nanometers across – was invented and it was <a href="https://en.wikipedia.org/wiki/History_of_the_transistor#The_first_transistor">40 micrometers long</a> (about 3,000 times longer than the current one). And in 1971 the first commercial microprocessor (the powerhouse of any electronic gadget) was <a href="https://en.wikipedia.org/wiki/Intel_4004">1,000 times bigger</a> than today’s when it was released.</p>
<p>The vast research efforts and the consequential evolution seen in the electronics industry are only starting in the photonic industry. As a result, current electronics can perform tasks that are far more complex than the best current photonic devices. But as research proceeds, light’s capability will catch up to, and ultimately surpass, electronics’ speeds. However long it takes to get there, the future of photonics is bright.</p><img src="https://counter.theconversation.com/content/68903/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Arnab Hazari's research group receives funding from the National Science Foundation, under MRSEC program.</span></em></p>As electronic transistors get tinier, they approach a point at which they won’t be able to get smaller. How can we keep shrinking our devices, and making them more powerful at the same time? Light.Arnab Hazari, Ph.D. student in Electrical Engineering, University of MichiganLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/486832015-12-16T19:29:43Z2015-12-16T19:29:43ZElectronics are getting small, and that is causing big problems<figure><img src="https://images.theconversation.com/files/103258/original/image-20151126-23847-m85z4v.jpg?ixlib=rb-1.1.0&rect=420%2C346%2C4101%2C2773&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The microprocessors on this wafer of silicon have transistors measuring in the nanometres.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Your television, computer, smartphone or any other electronic device wouldn’t work without being able to shuttle electric charges around their circuits.</p>
<p>Yet, as these devices gain in performance, with their individual components getting smaller and smaller – reaching the nanoscale – it becomes increasingly difficult to precisely channel these electric charges to where they’re needed. </p>
<p>In fact, at the nanoscale, some of these components behave in very strange ways, to the point where even a single atom can influence or disrupt the flow of electrons. A better understanding and control of these nanoscale dynamics is therefore crucial to improve their function.</p>
<h2>On the edge</h2>
<p>Transistors are the basic building blocks of microchips, and are found in everything from computers, to smartphones and amplifiers. Their function fundamentally depends on how electrons flow near or at the interfaces between their metallic, insulating and semiconductor materials.</p>
<p>Transistors today can be as small as 10 nanometres wide, and they’re getting smaller. If you have a smartphone in your pocket, it most probably has more than a billion transistors within. </p>
<p>As this miniaturisation trend continues, the performance of electronic components is more and more influenced by what happens to electrons at the boundaries of materials, since the likelihood of an electron being close to an interface increases as size decreases. </p>
<p>This is like if you find yourself in a room, then the smaller the room, the higher the probability that you will be standing next to a wall. </p>
<p>A similar phenomenon also affects solar cells, which generate electricity when positive and negative charges are separated within a few nanometers at the boundary between electron donating and electron accepting materials. </p>
<p>Light-emitting diodes can work the other way around: they can generate light when positive and negative charges recombine at these boundaries. </p>
<p>Organic molecules – similar to those responsible for photosynthesis in bio-organisms – with semiconducting properties are very promising materials for devices, such as transistors, solar cells and light-emitting diodes. </p>
<p>They are cost-effective, light, flexible and versatile. Their electronic properties are tuneable, and their production consumes less energy than that of silicon. </p>
<h2>Around the islands</h2>
<p>We <a href="http://www.nature.com/ncomms/2015/151006/ncomms9312/abs/ncomms9312.html">recently investigated</a> two-dimensional nano-clusters – or “nano-islands” – of different sizes and shapes, composed of organic semiconducting molecules on a thin insulator to see how electronic properties varied at different locations on them.</p>
<p>We used a scanning tunnelling microscope to determine the atomic-scale structure and electronic properties of the organic nano-islands. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/K64Tv2mK5h4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<p>The measurement of these currents allows us to create an image of the surface of the material to understand where atoms and electrons are located. These measurements were so sensitive that we had to perform them at a laboratory with extremely low vibrations at the University of British Columbia, in Canada. </p>
<p>Our experiments showed that the electrons of the molecules at the edge of the nano-islands behaved dramatically differently than those in the middle. Importantly, these differences in electronic behaviour depended strongly on subtle variations of position and orientation of the molecules nearby. </p>
<p>We found that when an electron is removed at a specific location in the centre of a nano-island, the electrons of the surrounding material react, moving towards the positive charge created by the electron removal. </p>
<p>Similarly, if an electron was added, the surrounding electrons moved away from the negative charge created by the electron addition. This collective motion of electrons polarises the surrounding environment and stabilises the created charge: the charge gets <em>screened</em>. </p>
<p>In contrast, when an electron is removed or added at the boundary of the nano-island – where transfer of electrons becomes important for technological applications – the created charge is screened a lot less efficiently. </p>
<p>Think of a crowded party where suddenly someone leaves the centre of the room, creating an empty space. The people dancing around will gradually occupy this spot a lot quicker than if the person had left the edge of the room. </p>
<p>This is not entirely surprising. What is surprising, though, is the magnitude of the effect. Our findings show that the energies involved in this are very large.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/97900/original/image-20151009-9146-bflng2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/97900/original/image-20151009-9146-bflng2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/97900/original/image-20151009-9146-bflng2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/97900/original/image-20151009-9146-bflng2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/97900/original/image-20151009-9146-bflng2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/97900/original/image-20151009-9146-bflng2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/97900/original/image-20151009-9146-bflng2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/97900/original/image-20151009-9146-bflng2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">3D representation of a scanning tunnelling microscopy image of a nano-island composed of twelve organic semiconducting molecules on a thin sodium chloride film. Electrons of boundary (red) and centre (purple) molecules behave dramatically differently.</span>
</figcaption>
</figure>
<h2>Tuning at the nanoscale</h2>
<p>Our work suggests a problem for the design of efficient nanoelectronic devices. Not only do subtle features of the nanoscale structure of components induce severe electronic effects at their interfaces, but also the influence of these effects becomes more important as the size of components shrink. </p>
<p>So it is crucial to control the arrangement of atoms and molecules at the interfaces between these components, and do this with incredible precision, in order to design new technologies with optimal efficiency and functionality. </p>
<p>Our findings open the door to new engineering approaches where the electronic properties of nano-devices can be tuned by small and precise variations of their atomic-scale structure. </p>
<p>This could be achieved by <a href="https://www.youtube.com/watch?v=oSCX78-8-q0">moving atoms and molecules</a> on a surface of a material in a controlled manner. Another possible way is to use supramolecular self-assembly, where atoms and molecules interact and automatically arrange themselves in desirable patterns at the nanoscale. </p>
<p>So while the effects we have discovered present a challenge for the future of nanoelectronic devices, they also present a terrific opportunity to develop faster and more efficient communication, information and electronic technologies.</p><img src="https://counter.theconversation.com/content/48683/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Agustin Schiffrin works for Monash University. </span></em></p><p class="fine-print"><em><span>Sarah A. Burke receives funding from the Natural Sciences and Engineering Research Council (Canada), Canada Research Chairs programme, Canadian Foundation for Innovation, and the University of British Columbia. </span></em></p><p class="fine-print"><em><span>Katherine Cochrane does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>As the components in electronic devices are shrinking to the nanoscale, even a single atom out of place can disrupt their function. But this also presents an opportunity to make them even better.Agustin Schiffrin, Lecturer in Physics, Monash UniversityKatherine Cochrane, PhD candidate in Atomic Imaging, University of British ColumbiaSarah A. Burke, Assistant Professor in Nanoscience, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/506642015-11-19T04:24:48Z2015-11-19T04:24:48ZThe big data challenge and how Africa can benefit<figure><img src="https://images.theconversation.com/files/102326/original/image-20151118-14214-1vxrw3o.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Large Hadron Collider is playing a key role in enabling the collection of big data. </span> <span class="attribution"><span class="source">Supplied</span></span></figcaption></figure><p><a href="https://theconversation.com/explainer-what-is-big-data-13780">Big data</a> has become some sort of celebrity. Everybody talks about it, but it is not clear what it is. To unpack its relevance to society it is important to backtrack a bit to understand why and how it came to be this ubiquitous problem.</p>
<p>Big data is about processing large amounts of data. It is associated with multiplicities of data formats stored somewhere, say in a <a href="http://searchcloudcomputing.techtarget.com/definition/cloud-computing">cloud</a> or in distributed computing systems. </p>
<p>But the ability to generate data systematically outpaces the ability to store it. The amount of data is becoming so big and is produced so fast that it cannot be stored with current technologies in a cost effective way. What happens when big data becomes too big and too fast?</p>
<h2>How fundamental science contributes to society</h2>
<p>The big data problem is yet another example of how the methods and techniques developed by scientists to study nature have had an impact on society. The techno-economic fabric that underlies modern society would be unthinkable without these contributions.</p>
<p>There are numerous examples of how findings intended to probe nature ended up revolutionising life. Big data is intimately intertwined with fundamental science and continues to evolve with it.</p>
<p>Consider just a few examples: what would life be without electricity or electromagnetic waves? Without the fundamental studies of <a href="http://www.phy.pmf.unizg.hr/%7Edpaar/fizicari/xmaxwell.html">Maxwell</a>, <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/1925/hertz-bio.html">Hertz</a> and other physicists on the nature of <a href="http://www.merriam-webster.com/dictionary/electromagnetism">electromagnetism</a> we would not have radio, television or other forms of wave mediated communication, for that matter.</p>
<p>Modern electronics is based on materials called <a href="http://dictionary.reference.com/browse/semiconductor">semi-conductors</a>. What would life today be without <a href="http://www.thefreedictionary.com/electronics">electronics</a>? The invention of transistors and eventually of integrated circuits is based entirely on the work scientists have done by thoroughly studying semi-conductors.</p>
<p>Modern medicine relies on countless techniques and applications. These range from x-rays, medical imaging physics and nuclear magnetic resonance to other techniques such as radiation therapeutic and nuclear medicine physics. Modern medicine and research would be unthinkable without techniques that were initially conceived for scientific research purposes.</p>
<h2>How the information age came about</h2>
<p>The big data problem initially emerged as a result of the need for scientists to communicate and exchange data.</p>
<p>At the European laboratory <a href="http://home.cern/">CERN</a> in 1990, internet pioneer <a href="http://www.w3.org/People/Berners-Lee/">Tim Berners-Lee</a> suggested a browser called <a href="http://www.w3.org/People/Berners-Lee/WorldWideWeb.html">WorldWideWeb</a>, leading to the first web server. The internet was born. </p>
<p>The internet has magnified the ability to exchange information and learn, leading to a proliferation of data.</p>
<p>The problem isn’t only about volume. The time lapsing between the generation and processing of information has also been greatly reduced.</p>
<p>The <a href="http://home.cern/topics/large-hadron-collider">Large Hadron Collider</a> has pushed the boundaries of data collection to limits never seen before.</p>
<p>When the project, and its experiments, were being conceived in the late 1980s scientists realised that new concepts and techniques needed to be developed to deal with streams of data that were bigger than had ever been seen before. </p>
<p>It was then that concepts that contributed to cloud and distributed computing were developed.</p>
<p>One of the main tasks of the Large Hadron Collider is to observe and explore the <a href="http://home.cern/topics/higgs-boson">Higgs boson</a>, a particle connected with the generation of mass of fundamental particles, by means of colliding protons at high energy. </p>
<p>The probability of finding a Higgs boson in a high-energy proton-proton collision is extremely small. For this reason it is necessary to collide many protons many times every second. </p>
<p>The Large Hadron Collider produces data flows of the order of petabytes every second. To give an idea of how big a petabyte is, the entire written works of mankind from beginning of written history, in all languages, can be stored in about 50 petabytes. An experiment at the Large Hadron Collider generates that much data in less than one minute.</p>
<p>Only a small fraction of the data produced is stored. But even this has already reached the exabyte scale (one thousand times a petabyte) leading to new challenges in distributed and cloud computing.</p>
<p>The <a href="http://www.ska.ac.za/about/index.php">Square Kilometre Array</a> (SKA) in South Africa will start generating data in the 2020s. SKA will have the processing power of about 100 million PCs. The <a href="https://www.skatelescope.org/">data</a> it collects in a single day would take nearly two million years to play back on an iPod.</p>
<p>This will produce new challenges for the correlation of vast amounts of data.</p>
<h2>Big data and Africa</h2>
<p>The African continent often lags behind the rest of the world when it comes to embracing innovation. Nevertheless big data is increasingly being seen as a solution to tackling poverty on the continent.</p>
<p>The private sector has been the first to get out of the starting blocks.
The bigger African firms are, naturally, more likely to have big data projects. In Nigeria and <a href="http://www.africanbusinessreview.co.za/technology/1783/Big-Data-in-Africa:-IBM-Dissects-a-Developing-Trend-in-a-Developing-Market">Kenya</a> at least 40% of businesses are in the planning stages of a big data project compared with the global average of 51%. Only 24% of medium companies in the two countries are planning big data projects.</p>
<p>Rich rewards can be reaped from harnessing big data. For example, healthcare organisations can benefit from <a href="http://www.hissjournal.com/content/2/1/3">digitising</a>, combining and effectively using big data. This could enable a range of players, from single-physician offices and multi-provider groups to large hospital networks, to deliver better and more effective services. </p>
<p>Grasping the challenge of managing big data could have big economic spin-offs too. With economies becoming more and more sophisticated and complex the amount of data generated increases rapidly. As a result, in order to improve these complex processes it is necessary to process and understand increasing volumes of data. With this labour productivity is enhanced. </p>
<p>But for any of these benefits to become reality, Africa needs specialists who are proficient in big data techniques. Universities on the continent need to start teaching how big data can be used to find solutions to scientific problems. A sophisticated economy requires specialists who are skilled in big data techniques.</p><img src="https://counter.theconversation.com/content/50664/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bruce Mellado receives funding from the DST, NRF and the University of the Witwatersrand. </span></em></p>Big data is about processing large amounts of data. It is often associated with multiplicities of data. But the ability to generate data outpaces the ability to store it.Bruce Mellado, Professor of Physics, University of the WitwatersrandLicensed as Creative Commons – attribution, no derivatives.