tag:theconversation.com,2011:/institutions/london-research-institute-1398/articlesLondon Research Institute2014-10-07T14:40:20Ztag:theconversation.com,2011:article/324562014-10-07T14:40:20Z2014-10-07T14:40:20ZYour phone screen just won the Nobel Prize in physics<p>You’ve probably got the fruits of this year’s Nobel laureates’ handiwork in your pocket. In fact, if you’re reading this on your phone or a relatively recent flat-screen monitor, you’re more than likely staring at some of them right now.</p>
<p><a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/2014/">The 2014 Nobel Prize in physics</a> has been awarded to <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/2014/akasaki-facts.html">Isamu Akasaki</a>, <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/2014/amano-facts.html">Hiroshi Amano</a> and <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/2014/nakamura-facts.html">Shuji Nakamura</a> for their pioneering work on blue LEDs, or light-emitting diodes. Blue LEDs are important for two reasons: first, the blue light has specific applications of its own and second, because it’s a vital component of the white light which makes white LEDs, and therefore LED computer and phone screens, possible.</p>
<h2>A flash of inspiration</h2>
<p>So, what is an LED? Fundamentally, the simplest LEDs are two pieces of <a href="http://en.wikipedia.org/wiki/Semiconductor">a semiconductor material</a> sandwiched together. Semiconductors, as their name suggests, are materials which don’t conduct electricity all that well.</p>
<p>This property might seem to demarcate them as thoroughly unremarkable, but in fact this propensity for unimpressive transmission of electrical currents has a huge advantage to technologists: its flexibility. If you take a semiconductor – silicon, for example – and mix in tiny amounts of impurities during manufacture, you can radically alter its electrical properties.</p>
<p>The two broad types of semiconductor you can make are called n-type and p-type. To make an n-type semiconductor, the impurity you add needs to be something which has lots of electrons. This gives the semiconductor an excess of electrons, and makes it a slightly better conductor of electricity.</p>
<p>A p-type semiconductor is the opposite: you add a chemical element which has a deficiency of electrons compared to the semiconductor around it, and you end up with an excess of “holes” – missing electrons, stolen from the semiconductor by the impurities you’ve added. (Counter-intuitively, this also increases the conductivity, because these holes can carry current too!) But it’s when you stick n-type and p-type together that the real magic happens. </p>
<p>Pass a current through your newly-manufactured p–n junction, and the electrons flow from the n-type material into the p-type, whereupon they promptly fall into the holes. As they plummet, they give off a tiny flash of light. </p>
<p>The colour of that light is determined by the semiconductor you’ve used. Silicon, for example, while great for computer chips, isn’t so brilliant for lighting. Light emitted by a silicon LED would be deep into the infra-red range, and invisible to the human eye. Infra-red LEDs are nonetheless very useful: they’re how your remote control allows you to zap instructions to your TV from your sofa. But even here, silicon isn’t used because for <a href="http://en.wikipedia.org/wiki/Direct_and_indirect_band_gaps">quite subtle reasons</a> it’s a very inefficient infra-red light source.</p>
<h2>Lightbulb moment</h2>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/61049/original/6cpmwt8h-1412688850.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/61049/original/6cpmwt8h-1412688850.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/61049/original/6cpmwt8h-1412688850.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/61049/original/6cpmwt8h-1412688850.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/61049/original/6cpmwt8h-1412688850.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/61049/original/6cpmwt8h-1412688850.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/61049/original/6cpmwt8h-1412688850.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The door to a Nobel.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/gnackgnackgnack/4154323430/sizes/l/in/photolist-7k6ZC3-95dV2b-7253Mg-7293wd-7253Bt-2kyd1-qXvPL-HNr9C-biLDXr-61XwJf-5yZ5oP-5yZ66X-5z4n1y-5z4npq-3TXm9p-kVFGcv-kVEgDU-ou1CN-6kpmGz-jjyy4C-6p5pkB-h1H8pU-2kkFA-61XwNm-kVL2La-2kkFy-cR2Gp-gYCr3H-6GNQQv-4a5R1b-2kgCm-2kqRE-2kkFB-2kkFz-4X8fJU-6HjJrL-6HjJos-ndGkcG-h3njwb-jjBinQ-is4dzp-7SeJW3-ubVAr-biLAVM-jraGQR-fmFMDR-4Knibr-7MYZnV-4kEXxV-4kEXzc-4kEXvx/">Patrick Brosset</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>So, if you want to manufacture an LED which emits a certain colour of light, you just need to find a material which has the right properties to give off the colour of light you’re interested in. In some cases this turns out to be quite simple. Red LEDs were available <a href="http://ledmuseum.candlepower.us/1960.htm">from the early 1960s</a>, using materials based on gallium arsenide. Green LEDs followed shortly thereafter using gallium phosphide. However, blue proved something of a challenge. The first commercially available blue LEDs came onto the market in 1989 and were based on silicon carbide but, much like pure silicon, they were phenomenally inefficient.</p>
<p>This is where our Nobel laureates step in. A better choice for producing blue light is gallium nitride (as you’ve probably noticed, gallium something-ide is where it’s at when it comes to making light from electricity). Unfortunately, it’s far trickier to coax bright light from this than the other gallium compounds. </p>
<p>First, it proved very hard to grow high-quality crystals of gallium nitride. Typically, it’s easiest to grow a crystal on a surface which has a similar crystal structure, but gallium nitride’s complex atomic layout makes that somewhat challenging. Then, making the LEDs more efficient requires a complex layering of even more materials, deviating somewhat from the idealised p–n junction LED we just met. Varying widths of the layers in this quantum sandwich can even alter the exact colour of light emitted (theoretically these “blue” LEDs could be tweaked to emit green, yellow or even orange light).</p>
<h2>From blue to white</h2>
<p>In spite of their complex manufacture, blue LEDs are now ubiquitous. For example, they can be found inside Blu-ray players. Blue light has a short wavelength, which allows the pits on a Blu-ray disc to be smaller and closer together than on a DVD, <a href="http://www.scientificamerican.com/article/whats-a-dvd-and-how-does/">which is read with red light</a>. This means that we can pack over five times as much data onto a disk the same size as a DVD.</p>
<p>Their biggest impact, however, is surely in giving us the ability to produce white LEDs. White light is actually a mixture of all the colours of the rainbow, as you can see if you split it up with a prism, or indeed if you catch a <a href="https://www.youtube.com/watch?v=ZowYVDQDDZ4">multicoloured reflection</a> in the surface of a Blu-ray disc, DVD or CD. However, the human eye has <a href="http://hyperphysics.phy-astr.gsu.edu/hbase/vision/colcon.html">just three types of colour receptor</a> inside it: red, green and blue.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/61054/original/29v4dfkt-1412690647.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/61054/original/29v4dfkt-1412690647.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/61054/original/29v4dfkt-1412690647.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/61054/original/29v4dfkt-1412690647.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/61054/original/29v4dfkt-1412690647.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/61054/original/29v4dfkt-1412690647.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/61054/original/29v4dfkt-1412690647.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">A Nobel Prize in your hand.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/highwaysagency/11235762823/sizes/l/in/photolist-i7SdQF-3wcTbc-nUszt2-mu88Ju-6TrRGS-9bnWFi-oq2r8z-nCh79p-bySXDx-8g4HF1-cdKWQA-kJ1f7r-maPTkS-cJawN-4TK6eD-8apr6p-2U28F-5z5baU-nUKPxV-8g1rH4-6bSThp-awfPTp-UFe2C-3wjpXk-4inwq2-3wep8T-6NKeLD-9p1wou-HctH2-7x6fxX-7gLtAT-agFyEa-8g4HYL-4cLKvG-maP7Nz-KomJ4-5NwjMu-UE9kX-4HCbFp-5vF2oF-HcuR4-4irAWj-6NQY8A-DNH41-aJBm4v-aPBv9X-hH4To6-o8P2RT-8asAUG-fKj2e-HcsXy/">Highways Agency</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>We can therefore make something which looks like white light using only these three colours. Combining red and green LEDs with blue ones allows us to create highly efficient white lighting, providing around 20 times as much light as an equivalent incandescent bulb. White LEDs are slowly making their way onto ceilings of homes, shops and factories around the world, but their real ubiquity today is as the back-light for computer and phone screens. Unlock your phone or turn on a recent flat-screen monitor, and red, green and blue LEDs shining through a layer of liquid crystal allows you to browse the web, watch movies, and even read this article.</p>
<p>As well as being a technological marvel, Akasaki, Amano and Nakamura’s Nobel Prize is a testament to tenacity in experimental science. As much as deft theoretical insight, the development of blue LEDs required hours of trial and error in the lab, performing the same procedures under subtly different conditions, trying to maximise the efficiency and cost-effectiveness of this finicky process.</p>
<p>The result is a technology which is all around us in the developed world, and making headway into the developing world too. These laureates’ bright idea could well be the light source of the 21st century and, when the movie version comes out, we can even watch their story on Blu-ray on an LED-backlit TV.</p><img src="https://counter.theconversation.com/content/32456/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Steele 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>You’ve probably got the fruits of this year’s Nobel laureates’ handiwork in your pocket. In fact, if you’re reading this on your phone or a relatively recent flat-screen monitor, you’re more than likely…Andrew Steele, Post-doctoral research fellow, London Research InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/247592014-03-31T13:43:43Z2014-03-31T13:43:43ZHow the #nomakeupselfie text gave cancer research funding a huge boost<figure><img src="https://images.theconversation.com/files/45166/original/z2yyk9m4-1396261673.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">In the name of science ...</span> <span class="attribution"><a class="source" href="https://twitter.com/morningireland/status/448069182765035520">morningireland</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>It wouldn’t normally be cause for celebration when something related to cancer goes viral, but the recent #nomakeupselfie trend has been <a href="http://scienceblog.cancerresearchuk.org/2014/03/25/nomakeupselfie-some-questions-answered/" title="Cancer Research UK: #nomakeupselfie—some questions answered">great news</a> for charity-funded cancer research. The campaign has already raised more than £8m, after women posted photos of themselves wearing no make-up to social media websites. So what sort of a contribution does this make to science funding? And how does that compare with the rest of the world’s charitable giving to scientific research?</p>
<p>During the #nomakeupselfie campaign, women <a href="https://twitter.com/CR_UK/status/446223117841494016" title="Twitter: Cancer Research UK">were encouraged</a> to post a ‘<a href="https://theconversation.com/note-to-selfie-youre-more-than-just-a-narcissists-plaything-20514">selfie</a>’, and then make a text-message donation of £3. That doesn’t sound like a lot of money, but in the UK only <a href="http://scienceogram.org/in-depth/health/" title="Scienceogram: Health">£5.20 per person per year</a> is spent on charity-funded cancer research. Many of those who donated won’t have thought twice about donating £3 and yet, taken on average, they have boosted personal charity funding of cancer research by nearly two-thirds.</p>
<p>When compared with research into other diseases, the numbers are even more stark: a £3 donation to stroke research would be more than eight times the research spend per person per year—for government and charity combined. This kind of comparison drives home the point that small investments in science can nonetheless make significant contributions.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/45162/original/6m3tpgmw-1396259964.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/45162/original/6m3tpgmw-1396259964.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/45162/original/6m3tpgmw-1396259964.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=190&fit=crop&dpr=1 600w, https://images.theconversation.com/files/45162/original/6m3tpgmw-1396259964.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=190&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/45162/original/6m3tpgmw-1396259964.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=190&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/45162/original/6m3tpgmw-1396259964.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=239&fit=crop&dpr=1 754w, https://images.theconversation.com/files/45162/original/6m3tpgmw-1396259964.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=239&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/45162/original/6m3tpgmw-1396259964.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=239&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="attribution"><span class="source">Scienceogram UK</span></span>
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<p>The combined economic impact of these diseases comes to more than <a href="http://scienceogram.org/in-depth/health/" title="Scienceogram: Health">£800 per person per year</a>—a figure combining the cost to the health service with other indirect costs to the economy, such as people giving up work as a result of their condition. This £800 is pitted against our combined research spend of around £13 from both government and charitable sources.</p>
<p>Thus, charity provides an important contribution to UK medical research – but its impact on science more generally is less significant. First, while charities researching specific diseases find it comparatively easy to raise funds (and it is important to emphasise the “comparatively” here – they are still only able to spend around £20 per year on behalf of the average UK citizen), it is not so easy to find charity support for research into less emotive and widely-known topics. </p>
<p>Whether you are researching fundamental organometallic chemistry, nuclear fusion, or even understanding <a href="http://www.publications.parliament.uk/pa/ld200506/ldselect/ldsctech/20/2011.htm#a92" title="House of Lords reports: Ageing—scientific aspects">the ageing process which gives rise to many of these diseases</a>, charity funding is relatively hard to come by. Taken across all areas of research, the UK non-profit spend on research and development is about eight times less than the £160 per capita spent by the government.</p>
<p>The UK is a world leader when it comes to charity-funded scientific research: spending of £20 per capita places the UK fourth in the world. In pole position, the US spends around £30 per person and, as you move down the rankings, the amount spent drops off significantly. Turkey, in 20th place, spends just £3.30 per capita on research funded by non-profits – equivalent to just over one #nomakeupselfie donation per person per year.</p>
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<a href="https://images.theconversation.com/files/45053/original/npmsqmzb-1396215671.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/45053/original/npmsqmzb-1396215671.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/45053/original/npmsqmzb-1396215671.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=557&fit=crop&dpr=1 600w, https://images.theconversation.com/files/45053/original/npmsqmzb-1396215671.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=557&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/45053/original/npmsqmzb-1396215671.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=557&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/45053/original/npmsqmzb-1396215671.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=700&fit=crop&dpr=1 754w, https://images.theconversation.com/files/45053/original/npmsqmzb-1396215671.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=700&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/45053/original/npmsqmzb-1396215671.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=700&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="attribution"><span class="source">Scienceogram UK</span></span>
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<p>Another source of potentially significant resources for scientific research is <a href="http://www.nytimes.com/2014/03/16/science/billionaires-with-big-ideas-are-privatizing-american-science.html" title="New York Times: Billionaires with big ideas are privatizing American science">high net-worth individuals</a>. From Bill Gates funding research into global health to Intel’s Gordon Moore donating towards projects from astronomy to ecology, the super-rich are making inroads into science funding. The world’s 100 wealthiest individuals are worth a combined £1.2 trillion, which is probably enough to develop nuclear fusion, add a few years to global life expectancy, send humans back to the Moon, and still have change.</p>
<p>However, loosening those purse strings will undoubtedly prove tricky: the $125bn offered by signatories to Bill Gates’s Giving Pledge represents around £70 per citizen of the developed world, or around three months’ worth of global public-funded spend on research and development. While still a significant amount of money, it seems clear that it won’t be supplanting state funding of science any time soon.</p>
<p>So, while non-profit funding makes up a significant fraction of medical research funding in certain countries, neither non-profits’ nor big philanthropic spending can replace the vital contributions made by the public and private sectors. The #nomakeupselfie campaign is one lens through which to view this: a £3 personal donation is both a lot, when it comes to charitable spending on research, and comparatively little, in the landscape of global funding of scientific research.</p>
<p>However, the success of #nomakeupselfie does demonstrate <a href="http://www.ipsos-mori.com/researchpublications/researcharchive/3357/Public-Attitudes-to-Science-2014.aspx" title="IPSOS Mori: Public Attitudes to Science 2014">a public appetite for supporting medical research</a>, and putting these numbers into context shows that a little extra money from each of us could make a difference. For those seeking an increase in science funding, while charitable donations can help, it is important to get governments on board too.</p><img src="https://counter.theconversation.com/content/24759/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Steele runs Scienceogram UK, a campaign raising awareness of the diminutive size of the governmen's spend on science compared to the size of the problems it is trying to solve.
He is funded by Cancer Research UK, but opinions expressed in this article are his own.</span></em></p>It wouldn’t normally be cause for celebration when something related to cancer goes viral, but the recent #nomakeupselfie trend has been great news for charity-funded cancer research. The campaign has…Andrew Steele, Post-doctoral research fellow, London Research InstituteLicensed as Creative Commons – attribution, no derivatives.