PyMS said:
btuser said:
LED bulbs are poised for another breakthrough. There is a new technique (accidental) of imposing voids within the Gallium Nitride which helps reduce the fissures caused by the two opposing crystaline lattices of Gallium Nitride and Sapphire. Its supposed to raise the efficiency/capacity by a factor of 10x. In 5 years they will be as cheap as CFLs
Sounds interesting. Could you provide a reference so I can read up on that?
Since I believe the efficiency of the latest commercially available LED lamps to be around 25%, I don't quite see how efficiency could improve another factor 10, even when allowing for the fact that a special class of solid state light emitting diodes (namely diode lasers) have occasionally been reportred to attain efficiencies > 100 % (by withdrawing heat from the environment).
Henk
Here's a link: (broken link removed to http://compoundsemiconductor.net/csc/news-details.php?id=19733011)
And another basically saying the same thing:
http://www.eetimes.com/electronics-news/4212526/GaN-process-said-to-reduce-defects-by-1-000X
It states right off the bat that for a given input of power the light output could be raise by a factor of 2. The power factor can also be raised because (forgive me for paraphrasing a subject completly over my head) there's still a lot of heat build up with LEDs, but instead of radiating from the bulb the heat buildup is behind the substrate, and that heat comes from the electrons being pushed around through the GaN and rubbing/hitting all the defects near the layers. By greatly reducing the number of these defects the LEDs can use a high wattage and not burn out. This may not be as efficient, but if I could get a true 40-70 watts from a single bulb, or a 300-1000 watt flood for say a warehouse or streetlamp/parking lot it could radically reduce my replacement costs.
And while we're on the subject of outdoor lighting, LEDs are dimmable so a parking lot or street lamps could be dimmed depending on light requirements instead of the currently on/off ballasts lights we have now. Say maybe 10%? Then, take it even farther with the fact that those same lights can be instantly switched on/off, so you wouldn't have to keep every light on in a parking lot if there wasn't anyone driving in that section.
This, however may not even be the most exciting application for this:
http://www.eetimes.com/electronics-news/4212526/GaN-process-said-to-reduce-defects-by-1-000X
Gallium Nitride is predicted to replace Silcone for chip making, and even MOSFETs needed for electric cars becasue they work well at high temperatures. Laptops that don't need fans, and IT closets that don't overheat July 4th weekend! LEDs' could replace lasers needed for single mode fiber-optics. Gallium Nitride maintains its power density at high frequency, so incredible radar/wireless applications are could become commercially viable with an improved manufacturing process like this. n
Here's an out-dated article that talks about the promise of this material. Interesting to me because it highlights the need for an improved substrate, and what that could do for the big picture: (broken link removed to http://www.semiconductor-today.com/features/SemiconductorToday) - Powering up GaN MOSFETs.pdf
The chart about 1/2 way down the page shows what engineers are up against when it comes to picking a surface to grow GaN crystals, and how dang handy it would be to be able to cope with the thermal expansion differences. Not just LEDs, but mobile devices, cell towers, wireless broadband, military radar, lots of stuff maybe happening because of accidental experiment in a lab not looking for it. I know it happens every day but still, pretty cool!