You all know that incandescent bulbs are pretty inefficient, converting only 10% of electricity into light — and 90% into heat. Light-emitting diodes, or LEDs, could soon replace incandescent and compact fluorescent bulbs in our homes. They are more efficient and environmentally friendly. But LED anchor light are currently too expensive because download aim they are using a sapphire-based technology. Now, Purdue University researchers have found a way to build low-cost and bright LED anchor light LEDs for home lighting.
According to the researchers, the LED anchor light now on the market cost about $100 while LED anchor light based on their new technology could be www.led.iecommercially available within a couple of years for a cost of about $5. It would also help to cut our electricity bill by about 10%, but read more…
You can see above how “Timothy Sands, at left, director of Purdue’s Birck Nanotechnology Center in Discovery Park, and graduate student Mark Oliver, operate a ‘reactor’ in work aimed at perfecting solid-state lighting, a technology that could cut electricity consumption by 10 percent if widely adopted.” car led lights(Credit: Purdue News Service; photo by David Umberger) Here is a link to a larger version of this photo.
The research team is not using expensive sapphire-based technology, but cheaper silicon-based one. “In the new silicon-based LED research, the Purdue engineers ‘metallized’ the silicon substrate with a built-in reflective layer of zirconium nitride. ‘When the LED emits light, some of it goes down and some goes up, and we want the light that latoya figueroa goes down to bounce back up so we don’t lose it,’ said Sands. Ordinarily, zirconium nitride is unstable in the presence of silicon, meaning it undergoes a chemical reaction that changes its properties. The Purdue researchers solved this problem by placing LED anchor light an insulating layer of aluminum nitride between the silicon substrate and the zirconium nitride. ‘One of the main achievements in this work was placing a barrier on the silicon substrate to keep the zirconium nitride from reacting,’ Sands said.”
And here are additional details provided by Emil Venere from Purdue University. “The Purdue team used a technique common in the electronics industry called reactive sputter deposition. The argon ions caused metal atoms to be ejected, and a reaction with nitrogen in the chamber resulted in the deposition of aluminum nitride and zirconium nitride onto the silicon surface. The gallium nitride was then deposited by another common technique known as organometallic vapor <a =http://www.eco-lights.com/]www.eco-lights.com[/url]phase epitaxy, performed in a chamber, called a reactor, at temperatures of about 1,000 degrees Celsius, or 1,800 degrees Fahrenheit.”
And for your ‘reading’ pleasure, here is the abstract. “An intermediate ZrN/AlN watch the dark knight online layer stack that enables the epitaxial growth of GaN on (111) silicon substrates using conventional organometallic vapor phase epitaxy at substrate temperatures of ~1000 °C is reported. The epitaxial (111) ZrN layer provides an integral back reflector led tail lights and Ohmic contact to n-type GaN, whereas the (0001) AlN layer serves as a reaction barrier, as a thermally conductive interface layer, and as an electrical isolation layer. Smooth (0001) GaN films less than 1 μm thick grown on ZrN/AlN/Si yield 0002 x-ray rocking curve full width at half maximum values as low as 1230 arc sec.”
The Rate Authority -- an alliance which represents 900,000 suburban residents LED anchor light on utility matters -- expects to report back to the cities on options later this year.作者: 學習至上 時間: 2008-8-13 10:58
這資料也叫資料嗎,以后少發這些資料作者: 瀟湘夜雨 時間: 2008-8-25 10:36 標題: 這是什么？ 文件下載后打不開？爛文件作者: bbzaiqe 時間: 2010-8-3 11:45
這個看了一下，為什么不說明是什么草呢？？？是干草還是濕的呢？？