Purdue University researchers have uncovered a potentially less expensive method to produce solid-state lighting based on light-emitting-diode (LED) technology. This development could hasten the day when LEDs, which are more energy efficient and longer lasting than conventional incandescent light bulbs, become the preferred lighting technology.
Existing LED lights are prohibitively expensive, in part because they are created on a substrate, or first layer, of sapphire. The sapphire-based LEDs require a separate mirror-like collector to reflect light that ordinarily would be lost. To overcome this problem, the Purdue researchers developed a means to create LEDs on low-cost, metal-coated silicon wafers, whereby the the silicon substrate is metalized with a built-in reflective layer of zirconium nitride.
According to Timothy Sands, professor of Materials Engineering and Electrical and Computer Engineering at Purdue, the silicon-based process will allow the scaling up of production using large silicon wafers, thus reducing cost. The widespread adoption of solid-state lighting could dramatically reduce the energy consumption and carbon emissions associated with generating electricity, as one-third of all electrical power consumed in the United States is from lighting.