The existing light emitting diode (LED) lamps in the market are both energy-saving and high-priced, but they are expensive. The European nanostructured semiconductor lighting research project participated by the University of Kassel in Germany is using the computer model to optimize the LED's light emitting structure. It is hoped that after a few years, a new type of LED lamp with low price and high brightness will be introduced.
At present, LED technology is mainly used to produce automobile taillights, traffic lights and displays. The cost for indoor lighting is still too high. An LED lamp equivalent to 60 watt incandescent lamp illumination costs about 30 euros in Europe. The main reason for this is that the sapphire substrate and gallium nitride epitaxial layer commonly used for producing LED lamps are expensive and the light emitting area is also limited.
The University of Kassel publishes a press communique that a new process being developed by researchers in the European nanostructured semiconductor lighting research project uses a low-cost silicon substrate instead of a sapphire substrate, and then uses complex nanotechnology to make the diameter about 100 nm and a height of about 3,000. Nanocrystalline hexagonal columns grow on silicon substrates. Compared to traditional processes, new technologies can produce larger and more compact light emitting surfaces in the same space.
Kassel University's contribution to this project is mainly to use a computer model to optimize the structure of the hexagonal light-emitting crystal pillars and make these semiconductor crystal pillars emit green, blue, and red light. Through these kinds of light mixing, LED can emit white light. In the past, in order to obtain a white light source, it is necessary to coat the surface of the LED with a fluorescent layer.
Prof. Witzelmann of the University of Kassel said that there are still several technical obstacles that need to be overcome for new LED lamps, from basic research to mature products. Researchers hope to launch the first demonstration sample by the end of 2012. It is estimated that this super LED light will be put into operation for at least 5 years. By that time, a new LED lamp with a luminous intensity comparable to that of a 75-watt incandescent lamp is expected to cost no more than 5 euros, and its service life will be about 10 times that of an incandescent lamp.
