New process could cut the cost of LEDs

Paul Boughton
A new way of making LEDs could see household lighting bills reduced by up to 75 per cent within five years. Gallium Nitride (GaN), the semiconductor from which LEDs (light emitting diodes) are manufactured, emits brilliant light yet uses very little electricity. Until now high production costs have made GaN lighting too expensive for widespread use.

However, with funding from the UK's Engineering and Physical Sciences Research Council (EPSRC), the Centre for Gallium Nitride, based at Cambridge University, has developed a new way of making GaN that could produce LEDs for one-tenth of current prices.

GaN, grown in labs on expensive sapphire wafers since the 1990s, can now be grown on silicon wafers. This lower-cost method could mean cheap mass-produced LEDs become widely available for general lighting in the next five years.

Based on current results, GaN LED lights in every home and office could cut the proportion of UK electricity used for lights from 20 per cent to 5 per cent, which means we could close or not need to replace eight power stations.

A GaN LED can burn for 100,000 hours so, on average, it only needs replacing after 60 years. And, unlike currently available energy-saving bulbs, GaN LEDs do not contain environmentally harmful mercury. GaN LEDs also have the advantage of turning on instantly and being dimmable.

Professor Colin Humphreys, lead scientist on the project said: "This could well be the holy grail in terms of providing our lighting needs for the future. We are very close to achieving highly efficient, low-cost white LEDs that can take the place of both traditional and currently available low-energy light bulbs. That will not just be good news for the environment; it will also benefit consumers by cutting their electricity bills."

GaN LEDs, used to illuminate landmarks like Buckingham Palace and the Severn Bridge, are also appearing in camera flashes, mobile phones, torches, bicycle lights and interior bus, train and plane lighting.

Parallel research is also being carried out into how GaN lights could mimic sunlight to help millions of people with seasonal affective disorder (SAD).

Ultraviolet rays made from GaN lighting could also aid water purification and disease control in developing countries, identify the spread of cancer tumours and help fight hospital 'super bugs.'

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