Light work

A man-made semiconductor used to make light-emitting diodes (LEDs) could reduce household lighting bills by up to 75 per cent within the next five years.

Gallium Nitride (GaN) emits bright light while using minimal electricity. It has been used to illuminate landmarks such as Buckingham Palace and the Severn Bridge, and has also been appearing in camera flashes, mobile phones, torches, bicycle lights and interior transport lighting. However, up until now it has been too expensive to be used in homes and offices.

Funded by the Engineering and Physical Sciences Research Council (EPSRC), the Cambridge University-based Centre for Gallium Nitride has been developing a new way of making GaN.

The centre is growing GaN on silicon wafers, rather than the expensive sapphire wafers that have been used since the 1990s. According to researchers, this brings down the cost of LEDs to a tenth of the current price and cuts the proportion of UK electricity used for lights from 20 per cent to five per cent.

On average, a GaN LED can burn for 100,000 hours and needs replacing after 60 years. GaN LEDs also have the advantage of being dimmable and turning on instantly, as well as being environmentally friendly during disposal.

Prof 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 won’t just be good news for the environment. It will also benefit consumers by cutting their electricity bills.’

In addition to reducing production costs, additional research is also being carried out to explore how GaNs can be used to help people with Seasonal Affective Disorder (SAD).

Ultraviolet rays from GaN lighting could also aid water purification, fight hospital ‘super bugs’ and identify the spread of cancer.