CONNECTING THE COMPOUND SEMICONDUCTOR COMMUNITY
July 2012 Volume 18 Number 5
Editor-in-Chief David Ridsdale
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Editor Richard Stevenson PhD
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Directors
Bill Dunlop Uprichard – CEO Stephen Whitehurst – COO Jan Smoothy – CFO Jackie Cannon, Scott Adams, Sharon Cowley, Sukhi Bhadal
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I’ve been mulling over what Toja had to say, and I’m not convinced that the best recipe for cost reductions in the silicon PV sector will deliver the best results in the LED industry. In my view, the headroom for improving the cost-per-Watt in silicon PV through technological advances is not that big - the main driver is efficiency, and many panels already deliver over half the theoretical maximum. In contrast, the opportunities to improve the performance of LEDs are massive.
One option is to make the LED much more efficient at high drive currents. Do this and there is less heating, so you can crank even more current through the chip until it finally reaches the temperature limit allowed in the bulb. This means that the operating current rises from hundreds of milliamps to several amps, and it is then possible to slash the number of LEDs in the bulb and its selling price.
The big barrier to driving LEDs harder is droop, a mysterious malady that causes efficiencies to decline as the current is cranked up. Many conjectures have been put forward in the last few years, and Fred Schubert’s team from Rensselaer Polytechnic Institute, in partnership with Samsung, Korea, are claiming that they now know the cause: Electron leakage from the active region. Their model can fit experimental data incredibly well (see page 45), and could help to devise droop-combatting LED architectures that will be welcomed by chipmakers. Take them on board and have success, and these chipmakers could help to drive down the price-per-lumen and fulfil my wish for far cheaper LED bulbs.
Richard Stevenson PhD Editor
debbie.higham@angelbc.com
For those LED chipmakers caught up in this bloodbath, there are two options for trimming manufacturing costs and maintaining margins: Streamline manufacturing processes; or turning to new, lower-cost technologies.
Speaking at the show, Marco Toja from the consultancy firm Luckygar argued that the focus for LED manufacturers should be on better production processes. He drew parallels with the silicon PV industry, where he says that efforts in China have delivered a six-fold slash in processing costs, enabling sales of $0.3/W panels. In comparison, performance improvement programs in Germany targeting better performance have only led to a halving of the cost-per-Watt.
jan.smoothy@
angelbc.com mitch.gaynor@
angelbc.com
I didn’t part with my cash - I’m going to wait for these bulbs to become more affordable, which should happen as reductions in the prices of packaged LEDs are passed on to consumers. LEDs account for the lion’s share of the cost of the bulb, and their price will fall, due to severe overcapacity in the market.
sharon.cowley@
angelbc.com E:
tbrun@brunmedia.com E:
jjenkins@brunmedia.com
I’VE just got back from EuroLEDs, a two-day conference that combines a collection of talks with a fairly large exhibition.
As I walked from booth to booth, I kept my eye out for an attractive 60 W-equivalent LED bulb. When I found one, I enquired of the price: Normally nearly £30, but 30 percent off that figure at the show.
robin.halder@angelbc.com shehzad.munshi@
angelbc.com Routes to more affordable LED bulbs
jackie.cannon@
angelbc.com david.ridsdale@angelbc.com
editorialview
July 2012
www.compoundsemiconductor.net 3
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