New Silicon Technology Lights The Way To Cheap LEDs
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According to reports from the US, a newly developed technique for building light-emitting diodes (LEDs) is set to bring low cost, energy efficient solid state lighting to households.

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The technique is designed to overcome the prohibitive costs of current LED manufacture by building the diodes on low cost silicon wafers, instead of sapphire.

LEDs are claimed to be four times more efficient than conventional incandescent lights, more environmentally friendly than compact fluorescent lights, and can have a lifespan of up to 15 years.

Purdue University researchers who developed the technique, claim this new LED technology could cut electricity consumption by 10 per cent.

Incandescent bulbs convert only 10 per cent of electricity into light, and the rest into heat, but by comparison, LEDs are designed to emit white light operate at efficiencies ranging from 47 to 64 per cent, but at present cost some 20 times more than conventional incandescent and compact fluorescent light bulbs.

Currently LEDs built on sapphire comprise a light-emitting material called gallium nitride but this new technique uses silicon wafers that are coated in a reflective metallic layer of zirconium nitride.


The big advantage of using silicon is that it dissipates heat better than sapphire, reducing damage caused by heating, which researchers expect will improve reliability and increase the lifetime of LED lighting.

There are two remaining hurdles in the manufacture of silicon-based LEDs: one is to reduce defects in the devices; and secondly, to prevent the gallium nitride layer from cracking as the silicon wafer cools down after manufacturing.

However, these engineering issues are not seen to be impossible to overcome and affordable, mass-produced LED lights should be on the market within two years, according to the experts involved in this research.