A new production method promises economical mass production so that LEDs could replace energy-saving bulbs.

Using LEDs for lighting bears the potential of dramatically reducing electric power costs for households. Previously, high production costs prevented widespread application of LEDs made of gallium nitride (GaN). However, now researchers at Cambridge University have succeeded in producing this material at significantly less cost; this could drop the costs of LEDs to 10%. Within five years cheap, mass-produced LEDs could become available, reports the Engineering and Physical Sciences Research Council (EPSRC), which financed the project.

Production costs reduced to 10%

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

Instead of growing gallium nitride LEDs on small, expensive sapphire wafers, the researchers succeeded in producing them with the help of smaller and cheaper silicon wafers. Nine times as many LEDs can be produced simultaneously and the production failure rate drops. The interplay of all these factors enables a cost reduction to 10%. The lower price would promote the acceptance of this lighting alternative.

Large-scale retrofitting of all lighting systems in homes and offices would have massive effects, according to EPSRC. The proportion of overall power consumption in the UK for lighting would drop from 20% to 5%, which could eliminate the need for eight power plants.

Gallium nitride LEDs generally glow green or blue, but in combination with a phosphorous layer they provide a highly energy-efficient source of white light. LEDs have a lifetime of some 100,000 hours. In contrast to energy-saving bulbs, they use no mercury and are suitable for dimming. In Great Britain, GaN LEDs are already used for illuminating landmarks such as Buckingham Palace and Severn Bridge (between south England and south Wales). Adding elements such as aluminum also makes ultraviolet LEDs feasible; these can be used in water treatment and in disease control.

Source: EurekAlert