The decline in the cost of awesome LED lighting cheap Era

Cost has always been a major obstacle to blocking the purchase of energy-efficient LED bulbs. Now, one of the world's largest LED manufacturer OSRAM Semiconductors semiconductor (Osram Opto), said it has improved technology, can significantly reduce the cost of production of LED.

Preparation of white LED, usually need to blue gallium nitride LED coated with yellow phosphor. Manufacturers usually produce thin layers of gallium nitride, which are carried out on expensive sapphire substrates. Instead, OSRAM made this device on a silicon substrate. The cost of the silicon substrate is more than 1/3 of the sapphire, and can even be cheaper because it can be made into larger sheets.

The company said that its silicon-based white LED watts per watt can produce 127 lumens, power efficiency of 58%, comparable to the most advanced commercial LED on sapphire. Peter · Peter (Stauss), is OSRAM's project manager, he said, researchers are testing and optimizing this device, expect to start selling them in the next two to three years.

OSRAM combined with several other companies, and strive to bring cheaper silicon gallium nitride led to the market. Power (Lattice) claims that it has started commercial production using the same technology. Last month, California (California) BridgELux, a new startup company, announced that it had worked with Toshiba to produce silicon-based light-emitting diodes. At the same time, Plaise British semiconductor company (Plessey Semiconductors) plans at the end of the year production of silicon based light emitting diode Gan, using the technology from the University of Cambridge (Cambridge University) owned company Caim Gahan (CamGaN). PHILPS and Samsung also said to be committed to silicon technology.

OSRAM did not say how much of its new LED will be cheaper, but both Puri and Plaise sound that the silicon process could reduce the production cost of LED by more than 75%. The company also predicts that its process can reduce the cost of 75 watts of the same LED bulbs, now sold at $40, down to $5.

It is easier and cheaper to manufacture large diameter silicon than sapphire, which can cut costs. Another attractive reason is that silicon can be turned to existing machines that were originally used to make silicon computer chips. The company has demonstrated a number of devices that are grown on 20 cm wide silicon wafers.

The challenge of developing gallium nitride on silicon is that these two materials have different rates of expansion and contraction. The light emitting diode is prepared at high temperature. When the material is cooled, the luminescence of the GaN layer will crack because of the tension with the silicon below. In order to solve this problem, OSRAM and other companies on the cultivation of other material films, such as aluminum nitride, around the gallium nitride, which can balance the tension generated during cooling.

Although many LED manufacturers have chosen silicon, but the California based start-up company Soraa (LA) is using gallium nitride substrate. This also reduces the mismatch between the two layers of crystal structure, and pull the chief technology officer Michael (Michael Krames) - Metz said, material defects reduced by 1000 times, which is to cultivate the contrast on silicon materials. The LED is more expensive than the use of silicon substrates, but they are also 10 times brighter, which helps offset the extra cost. "It's true that the LED performance is driving the total cost of the bulb," said Cramer J. In addition, this substrate is a small part of the overall cost of production. "

Now, although the star said that the cost advantage of the silicon substrate is more conducive to manufacturers, better than LED. "Gan substrates may be an option as long as they are much cheaper, but today there is no real opportunity to use them," he said.

Steve (Steve Denbaars) on bass is the California University of Santa Barbara (University of California, Santa Barbara) materials and electrical and Computer Engineering Professor, is also one of the founders and pull, he believes that gallium nitride and silicon substrate have a fair chance, can replace the sapphire. The gallium nitride will also have a performance advantage, he said, silicon has the opportunity to beat sapphire, just because there are many silicon manufacturing facilities, installed around the world. "

Cheaper to use: OSRAM has grown gallium nitride on 15 cm long silicon chips, made of high-performance white LED.