Sep 29 2010
Conventional electronics technologies are fast approaching their physical limits at a time when the demand for higher-quality images, faster communications and more compact electronics continues to build.
Light, rather than electrons, is expected to be the information carrier of the next generation of devices, promising higher speeds, power savings and enhanced sensitivity and selectivity. The use of light in such applications is a field of research known as photonics, and A*STAR researchers are making some impressive technological breakthroughs in this area.
The combination of red, green and blue is familiar to most of us as the three colors making up the pixels in our television sets and computer monitors. Together these three colors can produce any color, including white. LEDs of these three colors can fulfill the same role, but pure white emission in a single package is what is needed for applications such as display backlights. White LEDs are typically fabricated by adding yellow phosphor to a blue LED, which generates a ‘whitish’ light. The color is not perfect because energy losses in the phosphor introduce ‘gaps’ in the color spectrum.
Under the direction of Soo Jin Chua, a professor at the A*STAR Institute of Materials Research and Engineering (IMRE), researchers including Chew Beng Soh and Liu Wei are developing white LEDs that do not include phosphors. They have hit upon the idea of using nanometer-scale semiconductor crystals called ‘quantum dots’ instead.
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