Nitrides for the 21st century

我们的研究有可能挽救数百万人的生命，节省能源，减少碳排放，并实现完全安全的通信。它基于氮化镓，这可能是自硅以来最重要的新半导体。与硅不同的是，当小电流通过时，氮化镓会发出明亮的光。我们可以通过向氮化镓中加入越来越多的铟来产生任何颜色的光（例如蓝色，绿色，黄色，红色）。另一方面，如果我们在氮化镓中加入铝，我们可以产生紫外线。基于氮化镓的发光二极管（LED）和激光二极管已经被广泛使用，例如作为LED交通灯和作为最新DVD播放器的蓝光激光二极管。如果我们在蓝色LED上涂上一层黄色荧光粉，就会产生一种凉爽的白色光，这种白色LED被用作自行车前灯、手电筒、移动的手机的背光灯等。氮化镓的发光效率非常高，如果我们能够将基于白色氮化镓的LED用于家庭和办公室照明，我们可以节省15%的电力消耗，减少15%的发电站碳排放，并关闭8个大型发电站。然而，高功率白色LED对于家庭和办公室照明来说太昂贵，并且白色光的质量太差而不可接受。基于氮化镓的LED目前生长在两英寸直径的蓝宝石晶片上。我们正在六英寸的硅晶片上开发它们的生长。如果成功，这将使每个LED的成本降低十倍，这将使白色LED足够便宜，用于家庭和办公室照明。这需要一些具有挑战性的新科学，但我们在这项研究中处于世界领先地位。我们还计划通过开发新的绿色和红色荧光粉来生产高质量的白色光，就像自然阳光一样，我们将定制我们的LED的波长，以最大限度地激发这些新荧光粉。我们还计划完全消除荧光粉，这将进一步提高效率，并通过混合蓝色，绿色，黄色和红色LED产生白色光。目前，绿色和黄色LED由于不完全清楚的原因而具有相对差的效率，并且我们计划解决这个问题。解决成本和质量问题将为我们的家庭和办公室带来低成本、高效率、高质量的照明，并节省大量的能源和碳。深紫外线辐射可以阻止细菌和病毒繁殖，从而基本上杀死它们。目前，氮化铝镓LED在深紫外线下发光，但它们的效率太低而无法使用。我们建议制造在深紫外线中发射的高效LED。这些可以用来净化发展中国家的饮用水。世界上有10亿多人无法获得饮用水，饮用不纯净水导致的死亡人数超过艾滋病。我们的研究可以拯救数百万人的生命。LED的工作电压通常为4伏，因此可以由太阳能电池供电，非常适合发展中国家。此外，这种深紫外LED还可以用于手电筒，照射医院的墙壁、地板和床上用品，杀死超级细菌。我们计划开发一种称为单光子发射器的新型氮化镓基光源，它可以根据需要发射单个光子。这将用于发送完全安全的消息。例如，一个移动的电话，与一个单一的光子发射器，可以发送一个消息到一个自动取款机，让你得到钱，没有任何人获得您的银行详细信息，PIN码等的可能性，因此，我们的研究承诺，我们的社会的健康，财富，福祉和安全的实质性好处。

Our research has the potential to save millions of lives, save energy, save carbon emissions and enable totally secure communications. It is based on gallium nitride, which is probably the most important new semiconductor since silicon. Unlike silicon, gallium nitride emits brilliant light when a small electric current is passed through it. We can produce light of any colour (for example blue, green, yellow, red) by adding more and more indium to gallium nitride. On the other hand, if we add aluminium to gallium nitride we can produce ultra-violet light. Gallium nitride based light emitting diodes (LEDs) and laser diodes are already in widespread use, for example as LED traffic lights and as Blu-ray laser diodes for the latest DVD players. If we coat a blue LED with a yellow-emitting phosphor then a cool white light is produced, and such white LEDs are used as front bicycle lights, flashlights, backlighting for mobile phones, etc,The aim of this Platform Grant is to underpin our research in a number of key areas. Gallium nitride produces light so efficiently that if we could use white gallium nitride based LEDs for home and office lighting we could save 15% of all electricity used, reduce carbon emissions from power stations by 15% and close eight large power stations. However, high-power white LEDs are too expensive for home and office lighting, and the quality of the white light is too poor to be acceptable. Gallium nitride based LEDs are currently grown on two-inch diameter sapphire wafers. We are developing their growth on six-inch silicon wafers. If successful, this will reduce the cost of each LED by a factor of ten, which will make white LEDs cheap enough for home and office lighting. Some challenging new science in required for this, but we are world leading in this research. We are also planning to produce high quality white light, like natural sunlight, by developing new green and red phosphors, and we will tailor the wavelength of our LEDs to maximise the excitation of these new phosphors. We also plan to eliminate phosphors totally, which will further improve the efficiency, and produce white light by mixing blue, green, yellow and red LEDs. Currently green and yellow LEDs have relatively poor efficiency, for reasons which are not totally clear, and we plan to solve this problem. Solving both the problems of cost and quality will yield low-cost high-efficiency high-quality lighting for our homes and offices, with the substantial energy and carbon savings referred to above.Deep ultra-violet radiation stops bacteria and viruses from reproducing and hence essentially kills them. Aluminium gallium nitride LEDs at present emit in the deep-UV, but their efficiency is too low to be useful. We propose to make highly-efficient LEDs emitting in the deep-UV. These could be used to purify drinking water in the developing world. Over one billion people in the world do not have access to drinkable water, and drinking impure water kills more people in the world than AIDS. Our research could lead to literally millions of lives being saved. The LEDs operate at typically 4 Volts and so can be powered by solar cells, ideal for the developing world. Additionally such deep-UV LEDs could be used in a flashlight to shine on hospital walls, floors and bedding to kill superbugs.We plan to develop a novel gallium nitride based light source called a single photon emitter, which emits a single photon on demand. This would be used for sending totally secure messages. For example a mobile phone, with a single photon emitter, could send a message to a cash machine for you to obtain money, with no possibility of anyone obtaining your bank details, PIN number, etc. Our research therefore promises substantial benefits to the health, wealth, wellbeing and security of our society.