Science Bridge Award USA: Harnessing Materials for Energy

Lead Research Organisation: University of Cambridge
Department Name: Materials Science & Metallurgy

Abstract

This Science Bridge proposal builds upon the existing collaboration between the University of Cambridge and the University of California at Santa Barbara to perform the research required to bring existing research through to prototype products and devices in the field of energy-related materials. The proposal has five key themes: organic and inorganic solar cells; light emitting diodes (LEDs) based on gallium nitride (GaN); phosphors for solid-state lighting; organic LEDs (OLEDs); the low-cost integration of LEDs and OLEDs onto printed circuit boards; and ultralight materials and structures.An hour of solar radiation on the Earth provides 14 Terawatt-years of energy, almost the same as the world's total annual energy consumption. However, currently solar energy contributes only 0.03% of the world's energy needs, the main barriers to the widespread use of solar energy being cost and efficiency. The cost of solar cells (typically based on Si or CdTe) is currently too high by a factor of ten relative to other energy sources. The efficiency of solar cells is only 10-15% for Si and 20% for CdTe. We propose two approaches to make solar energy more viable. First, we propose to develop moderate-efficiency (about 15%) organic solar cells at extremely low-cost. UCSB will concentrate on developing more efficient cells and Cambridge will address low-cost manufacturing methods. This requires significant advances in printing methods for organic film deposition.The other approach to solar cells we will pursue is high-efficiency inorganic multilayer solar cells. The basic idea is that by stacking layers in the order of their bandgap, with the layer with the largest bandgap at the top, light is converted into electricity in the most efficient way. We propose to build an innovative multi-layer solar cell based on GaN/InGaN/Si. The GaN layer will absorb the UV part of the solar spectrum, the InGaN layer the blue and green parts and the Si layer the yellow, red and near-IR parts. The theoretical efficiency is above 60%. Such a cell would be too expensive for large-area applications, but would be designed to be used at the focus of mirrors that concentrate the solar light, which will make the technology competitive.GaN-based white lighting is extremely efficient and if used in our homes and offices it could save 15% of the electricity generated at power stations, 15% of the fuel used, and reduce carbon emissions by 15%. However for GaN-based white lighting to become widely used in homes and offices we have to increase the efficiency still further and reduce the cost. We will research various ways to increase the efficiency. To reduce the cost we will grow GaN-based LED structures on 150mm (six-inch) silicon wafers instead of the current growth on two-inch sapphire wafers. This would reduce the LED cost by a factor of ten. Cambridge will grow such LED structures and UCSB will process them into LED lamps.Current white LEDs mainly use a blue LED coated with a yellow phosphor, which gives a cold white light. We will research novel phosphors which give excellent colour rendering, so that skin tones, the colour of clothes, etc, look the same indoors and out. There is increasing evidence that such natural lighting is better for our health than poor quality artificial lighting. We will research OLEDs for large area applications in both displays and lighting. We will also develop the low-cost integration of both LEDs and OLEDs onto printed circuit boards, which will facilitate and reduce the cost of using LEDs and OLEDs.Finally, we will develop novel ultralight materials and structures for use in cars, buses, lorries, trains and planes. These are cellular materials like a honeycomb or 3D lattice. We will develop these using both polymers, metals and composites. Such ultralight materials/structures should save considerable amounts of energy when used in transportation systems such as cars, buses, trains and planes.

Publications

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Moram M (2009) On the origin of threading dislocations in GaN films in Journal of Applied Physics

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Moram M (2009) X-ray diffraction of III-nitrides in Reports on Progress in Physics

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Naresh-Kumar G (2014) Coincident electron channeling and cathodoluminescence studies of threading dislocations in GaN. in Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada

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Oehler F (2013) Surface morphology of homoepitaxial c-plane GaN: Hillocks and ridges in Journal of Crystal Growth

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Oehler F (2013) Fundamentals of X-ray Diffraction Characterisation of Strain in GaN Based Compounds in Japanese Journal of Applied Physics

 
Description Three spin-out companies have been formed through the research performed on this grant. One of these, PervasID, arose from the research performed by the group of Professor White. Two of his post-docs supported on this grant, Dr Crisp and Dr Sithamparanathan, formed a new spin-out company in 2011, PervasID, largely based on the research they performed on this grant. The research developed RFID tags to provide location information through accurate wireless tracking and sensing. The company is applying this in several sectors, including retail, security and logistics. It can also detect files in medical or legal offices, for example. Existing RFID tags used on clothing and other items have a detection range of only a few metres, and so a shop assistant has to check each tag with a handheld reader. The PervasID system uses a network of antennas. providing extensive coverage over a large area, such as a large building. It is new technology that satisfies an unmet need. Apart from the new company, the work on this grant has let to White's group being awarded two follow-on grants from the EPSRC and one from Boeing.
A further major success has been the work performed by Professors Deshpande and Fleck, in collaboration with UCSB in the USA. They have been working on the development of new ultra-lightweight materials and structures. These are cellular materials like a honeycomb or 3D lattice. Such ultralight materials/structures should save considerable amounts of energy when used in transportation systems such as cars, buses, trains and planes. Their work on new lightweight energy absorbing materials has been taken up by HRL Laboratories in Malibu, California. It has also formed the basis of two new projects in Cambridge funded by DARPA. In collaboration with UCSB, they have developed a model for optimising the use of ceramic materials in vehicle applications. In addition to the grants from DARPA mentioned above, their work has resulted in two further follow-up grants to Cambridge from the USA Office of Naval Research.
The vision of the Humphreys' research group was to grow GaN LEDs on large-diameter (6-inch) Si wafers. This Science Bridge Award enabled us to develop this research, apply for a patent, set up a company, CamGaN, in 2010 and another company, Intellec, in 2011. Both companies were acquired by the UK company Plessey in 2012, which also hired 3 of Humphreys' post-docs who transferred the technology. We were told that it would take two years to transfer the technology from our university to Plessey. In fact it took only eight weeks. Plessey has been manufacturing since 2013 millions of GaN LEDs on Silicon at its factory in Plymouth based on our technology. Plessey has stated that our technology will reduce the cost of GaN LEDs by factor of 5, so that a 60W replacement light bulb should cost less than £5. in fact it now (March 2019) costs only £3. Further economies of scale should enable the widespread adoption of LED lighting in our homes and offices, which is already happening (March 2019). When LED lighting is even more widespread in the UK, which will happen in the next few years, this will save the UK £2 billion pa electricity costs and 10% CO2 emissions from power stations. Our research has also created the first ever manufacturing of GaN LEDs in the UK, at Plessey in Plymouth. Plessey are now (2019) making the best microLEDs in the world, with a diameter as small as 1 micron, for use as displays in smart watches, mobile phones and cameras, where the image is visible in bright sunlight.
In summary, this grant has resulted in a number of very successful outcomes.
Exploitation Route Our findings are already being used by various industries, please see statements above
Sectors Aerospace, Defence and Marine,Construction,Digital/Communication/Information Technologies (including Software),Electronics,Energy,Environment,Healthcare,Manufacturing, including Industrial Biotechology,Transport

URL http://www.gan.msm.cam.ac.uk
 
Description Many shop sales are lost because the shopper can't find the size he or she wants, even though the item might be available in the stockroom. A major success of this grant was the research performed by the group of Professor White to solve this problem. Two of his post-docs supported on this grant, Dr Crisp and Dr Sithamparanathan, formed a new spin-off company in 2011, PervasID, largely based on the research they performed on this grant. The company won its first order in 2013 and secured investment of £720,000 in 2016 to take the business to the next level. PervasID has launched the world's first cost-effective and nearly 100 percent accurate, wide area RFID system for retail shops, which will automate real-time inventory management and stock control and remove the need for handheld readers. Passive RFID tags currently used on clothes and other items are cheap and don't need batteries, but have a reliable detection range of only 2-3 metres and so require the shop assistant to check each tag with a handheld reader. The next generation PervasID system uses a network of antennas located discreetly at intervals across the shop floor and stockroom. A single RFID reader can cover up to 400 m2 with almost 100 percent detection accuracy, capable of easily scaling to a large building, allowing automatic monitoring of nearly all the tags and constant update of stock control. Low cost, long distance sensing of passive RFID tags is an unmet need in the retail and logistics industries. PervasID is a technology game changer that facilitates a move towards the 'Internet of Things'. Apart from the new company, the work on this grant has let to White's group being awarded two follow-on grants from the EPSRC and one from Boeing. A further major success has been the work performed by Professors Deshpande and Fleck, in collaboration with UCSB in the USA. They have been working on the development of new ultra-lightweight materials and structures. These are cellular materials like a honeycomb or 3D lattice. Such ultralight materials/structures should save considerable amounts of energy when used in transportation systems such as cars, buses, trains and planes. Their work on new lightweight energy absorbing materials has been taken up by HRL Laboratories in Malibu, California. It has also formed the basis of two new projects in Cambridge funded by DARPA. In collaboration with UCSB, they have developed a model for optimising the use of ceramic materials in vehicle applications. In addition to the grants from DARPA mentioned above, their work has resulted in two further follow-up grants to Cambridge from the USA Office of Naval Research. A further success story has been our development of low-cost LED (light emitting diode) lighting. This research on this grant was performed in parallel with my grants "Nitrides for the 21st Century" and "Lighting the Future". The three grants together gave me the manpower required. This Science Bridge Award funded the more developmental aspects of the research and paid for our key Patent, which enabled us to move fast on the patenting and was extremely helpful. LED lighting will save the UK £billions per year in electricity costs and has been commercialised in the UK by Plessey, thanks to our EPSRC support. Electricity generation is the main source of energy-related greenhouse gas emissions. Lighting uses one-fifth of its output. LEDs are poised to reduce this figure by 50%. Lighting will then use 10% of all electricity, which will save 10% of the electricity generated in power stations and save 10% of the CO2 emissions from power stations. If the UK changed to LED lighting in our homes and offices we could close (or not build) 10 large power stations (or hundreds of wind turbines) and save £2 billion pa electricity costs. The reason this did not happen earlier was cost. Whereas low-power LEDs are cheap, costing only a few pence, high-power LEDs for lighting were expensive. For example, a Philips 60W replacement bulb (using 12W LEDs) cost £25 in 2013, and not many people would pay this cost. All commercial GaN LEDs were grown on small-diameter sapphire or SiC wafers, which is why they were expensive. The vision of the Humphreys' research group was to grow GaN LEDs on large-diameter (6-inch) Si wafers. This Science Bridge Award enabled us to develop this research, apply for a patent, set up a company, CamGaN, in 2010 and another company, Intellec, in 2011. Both companies were acquired by the UK company Plessey in 2012, which also hired 3 of Humphreys' post-docs who transferred the technology. Plessey is manufacturing at its factory in Plymouth (an unemployment blackspot) millions of LEDs per year based on our technology. Production started in the summer of 2013. Our technology reduces the cost of GaN LEDs by factor of 5, so that a LED 60W replacement light bulb should cost less than £4 (note added in 2019: it now costs only £3). Economies of scale will reduce the price further and enable the widespread adoption of LED lighting in our homes and offices, which is now happening. GaN LEDs will save the UK £2 billion pa electricity costs and 10% CO2 emissions from power stations. Our research has also created the first ever manufacturing of blue and white LEDs in the UK. In summary, this grant has resulted in a number of very successful outcomes.
First Year Of Impact 2012
Sector Construction,Digital/Communication/Information Technologies (including Software),Electronics,Energy,Environment,Healthcare,Manufacturing, including Industrial Biotechology,Retail,Transport
Impact Types Societal,Economic

 
Description Science Policy (Round Table meetings at No. 10 and BIS)
Geographic Reach National 
Policy Influence Type Participation in advisory committee
Impact Increased funding for materials research has resulted. This will have economic impacts and on the quality of life
 
Description EPSRC
Amount £560,766 (GBP)
Funding ID EP/J003603/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 04/2009 
End 10/2012
 
Description EPSRC
Amount £6,361,650 (GBP)
Funding ID EP/I012591/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 12/2010 
End 11/2015
 
Description EPSRC
Amount £826,500 (GBP)
Funding ID EP/H019324/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 11/2009 
End 10/2014
 
Description Platform Grant
Amount £826,500 (GBP)
Funding ID EP/H019324/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 11/2009 
End 10/2014
 
Description Programme Grant: Lighting the Future
Amount £6,361,650 (GBP)
Funding ID EP/I012591/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 12/2010 
End 11/2015
 
Description Study of semi-polar and non-polar nitride based structures
Amount £560,766 (GBP)
Funding ID EP/J003603/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 01/2012 
End 12/2014
 
Description Aixtron 
Organisation Aixtron Limited
Country Unknown 
Sector Private 
PI Contribution We grew world class GaN device structures on our Aixtron reactor(s), thus increasing Aixtron sales.
Collaborator Contribution They donated to us a senior scientist for 25% of his time. They provided free servicing and maintenance of our growth reactor.
Impact Increased sales of Aixtron growth reactors.
 
Description Plessey collaboration 
Organisation Plessey Semiconductors Ltd
Country United Kingdom 
Sector Private 
PI Contribution We developed a new low-cost high-efficiency method for making GaN LEDs. we set up two companies which Plessey acquired. Plessey also hired 3 of my post-docs to transfer the technology and as permanent hirings. We continue to collaborate with Plessey, providing them with advice. We also provided them with two growers for a period of three months when their main grower left in 2016.
Collaborator Contribution Plessey process LED structures that we grow and we exchange information. The processing of our wafers is very important for our research.
Impact Plessey are manufacturing GaN-on-Si LEDs at Plymouth based on our technology. This is the first and only manufacturing of GaN LEDs in the UK. Plessey had the first commercially available GaN LEDs on large area Si in the world, based on our Cambridge technology, funded by the EPSRC. Plessey raised £30 million from the Deutsche Bank and £30 million from other investors in 2015 to expand their GaN-on-Si LED manufacturing. The are employing over 100 people in Plymouth in LED manufacturing. They are manufacturing millions of LEDs per year. Materials Science, Physics, Chemistry, Electronics.
Start Year 2010
 
Title GaN on Si device substrate with GaN layer including sub-10nm SiNx interlayers that promote crystal growth with reduced threading dislocations 
Description The present invention relates to a semiconductor material and the use of a semiconductor material in wafer form as a support for forming a light emitting diode (LED) or other optoelectronic device. Further, the present invention relates to a method of constructing high quality optoelectronic devices using the wafer. In particular, the present invention relates to an improved LED having a silicon substrate that minimises the dislocation-defects that occur when larger support wafers are used. A gallium nitride (GaN) semiconductor substrate for grown of nitride semiconductor devices comprises an underlying wafer that carries a first GaN layer that has one or more very thin silicon nitride SiNx inter-layers therein. These Si N x inter-layer(s) are 0.5nm to 10nm thick and the GaN penetrates through one or more portions of the inter-layer preferably to form discrete crystalline structures (3D GaN). Preferably these crystalline structures help reduce threading dislocations when the GaN layer is grown, by MOVPE for example. Additionally, below the GaN layer, an aluminium nitride AlN nucleation layer may lie on the underlying wafer with an aluminium gallium nitride AlGaN buffer layer above the AlN and below the GaN layer. The underlying wafer may be silicon Si.; The AlGaN layer may have a graded alloy content so the amount of aluminium decreases from the Si wafer towards the GaN layer. The GaN layer may be undoped and a second, doped, GaN layer may be formed on top, the dopant concentration of Si or Ge increasing with increasing distance from the first undoped GaN layer. Devices may be formed including MQW structures which may comprise LED or Solar (photovoltaic) devices. The substrate may be from 6 inches (15cm) to 12 inches (30cm) in diameter. 
IP Reference WO2012066269 
Protection Patent granted
Year Protection Granted 2010
Licensed Yes
Impact This patent was transferred to a Cambridge spin-out, CamGaN Ltd, for commercial exploitation of the technology described in the patent. CamGaN was later acquired by Plessey semiconductors in 2012. A portfolio of products based on the CamGaN technology has been launched by Plessey and has generated positive market feedback.
 
Title SEMICONDUCTOR MATERIAL 
Description The present invention relates to a semiconductor wafer comprising: a substrate; a first AlGaN layer on the substrate; a second AlGaN layer on the first AlGaN layer; a Ga N layer on the second AlGaN layer; and a plurality of crystalline GaN islands between the first and second AlGaN layers. 
IP Reference WO2014053831 
Protection Patent application published
Year Protection Granted 2012
Licensed Commercial In Confidence
Impact This development will reinforce the GaN-on-Si technology developed in Cambridge centre for GaN, which provides an alternative way to achieve high performance GaN-on-Si LEDs. Commercial exploitation of this discovery is under discussion.
 
Company Name CamGaN 
Description Set up to exploit GAN LEDs on 6 inch Silicon. 
Year Established 2010 
Impact CamGaN was formed in 2010 to commercialise a novel technology (GaN LEDs on large-area (150 mm diameter) silicon) for the cost-effective manufacture of key components of high-brightness LEDs. This novel technology holds strong potential to dramatically reduce the cost of solid-state lighting devices that are rapidly replacing incandescent and fluorescent light bulbs. Plessey acquired CamGaN in 2012. In 2014 they manufactured over 2 million LEDS based on this technology. Recently they have raised £60m to expand production capacity and this will employ 400 more people in Plymouth. The widespread use of LED lighting in the UK will save 10% of all our electricity used and 10% of carbon emissions from power stations. We are continuing to develop this work on current EPSRC grants. See also my entry under my spin-out company Intellec.
Website http://www.enterprise.cam.ac.uk/news/cambridge-spin-out-camgan-acquired-by-plessey/
 
Company Name PervasID 
Description The company provides accurate wireless tracking and sensing 
Year Established 2011 
Impact The company recently raised over £800,000 in investments to take its products to the next level, for use in retail, security and logistics.
Website http://www.pervasid.com
 
Company Name INTELLEC LTD 
Description To further exploit our low-cost GaN LEDs on large area silicon. 
Year Established 2011 
Impact Intellec and CamGaN were taken over by Plessey in 2012. Plessey are now manufacturing millions of LEDs each year based on our technology. They are manufacturing in the UK, in Plymouth. Over 100 people are employed by Plessey in the UK on manufacturing our LEDs. Plessey raised £30 million from Deutsche Bank and £30 million from other investors in September 2015 to expand their manufacturing capabilities. Humphreys is a member of the Plessey Advisory Board. We continue to work with them on a variety of EPSRC grants. See also the entry under my spin-out company CamGaN.
Website http://www.endole.co.uk/profile/15411715/colin-john-humphreys
 
Description BBC Breakfast TV and BBC Radio "You and Yours" 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Interview of Prof Humphreys on BBC Breakfast TV, and on the BBC Radio "You and Yours" on low-cost LEDS sparked a lot of discussions

Increased public awareness of LEDs
Year(s) Of Engagement Activity 2009
 
Description Big Bang Fair (London) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Geographic Reach National
Primary Audience Schools
Results and Impact Encouraged school pupils to study science

Schools reported increased interest in science and increased numbers studying science
Year(s) Of Engagement Activity 2013,2014
 
Description Chelterham Science Festival 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Geographic Reach National
Primary Audience Schools
Results and Impact More school pupils studying science

Schools reported greater interest in science.
Year(s) Of Engagement Activity 2013,2014