A quantum dot is a particle of matter so small that the addition or removal of an electron changes its properties in some useful way. All atom s are, of course, quantum dots, but multi-molecular combinations can have this characteristic. In biochemistry, quantum dots are called redox groups. In nanotechnology , they are called quantum bits or qubit s. Quantum dots typically have dimensions measured in nanometers, where one nanometer is 10 ^-9 meter or a millionth of a millimeter.

The fields of biology, chemistry, computer science, and electronics are all of interest to researchers in nanotechnology. An example of the overlapping of these disciplines is a hypothetical biochip , which might contain a sophisticated computer and be grown in a manner similar to the way a tree evolves from a seed. In this scenario, the terms redox group and qubit are equally applicable; it is hard to classify such a chip as either animate or inanimate. The quantum dots in a biochip would each account for at least one data bit, and possibly several.

In the extreme, the position of a single electron in a quantum dot might attain several states, so that a quantum dot could represent a byte of data. Alternatively, a quantum dot might be used in more than one computational instruction at a time. Other applications of quantum dots include nanomachines , neural networks, and high-density memory or storage media.

21 Sep 2005