Interest in nanotechnology can be traced back to an influential 1959 talk by Richard Feynman, the famous Nobel Prize-winning physicist. During that speech, Dr. Feynman argued that scientists and engineers alike needed to begin studying ways to build the equipment necessary to work at atomic dimensions. Because an atom is roughly 0.10 nm, nanotechnology is often described as the application of molecular systems or atomic particles.

The capability to design and fabricate electronics at the atomic level represents a breakthrough in technology. Yet there is nothing magical about nanotechnology. It is the next logical advancement after microtechnology, which focused on micron-level entities (one-millionth of a meter). For proof, look at the microelectromechanical-systems (MEMS) devices of today. They are expected to evolve into even smaller components. Essentially, they will become the nanoelectromechanical-systems (NEMS) devices of tomorrow.

In the 1960s, advances in material science were a prerequisite for the creation of early semiconductor technologies. Similarly, advances in nanotechnology will require a more mature understanding of nanoscale materials. When this understanding is attained, numerous applications will emerge in the fields of electronics, optics, and biology.

One of the alluring features of nanotechnology is its ability to allow the development of chips beyond silicon semiconductors. When fully realized, nanoscale electronics will provide hard disks of incredible density and extremely small size, such as those demonstrated by researchers at the State University of New York's Albany campus (www.albany.edu). Or consider IBM's (www.ibm.com) thermomechanical-storage "Millipede" project. The company successfully demonstrated a data storage density of 1 trillion bits per square inch—20 times higher than the most dense magnetic-storage system currently available.

Nanometer-scale materials are also being demonstrated in display technology. For example, Applied Nanotech, Inc. (www.sidiamond.com) recently showcased a 14-in. nanotube display.

While nanotechnology remains in its infancy, the nanoscale product market is estimated to have a total potential of $300 billion per year within 10 years. It is forecasted for another $300 billion per year for global integrated-circuit sales. But these revenue potentials will only be realized if the theory of nanoelectronics can find practical applications.

Why should designers of today's wireless systems be interested in nanotechnology? Though there are several reasons, the most compelling one is probably that many designs are already taking place at 130 nm. Now, the relentless dictates of Moore's Law are pushing the scale even lower. The development and production of chips at the 65-nm scale is only two generations away.

In addition, several major companies in the U.S. and Europe intend to launch commercial products within the next three to seven years. This means that the design tools and manufacturing processes for these products are being developed now.

Skip Rung, former head of the Oregon branch of Research and Development for Hewlett Packard (www.hp.com), recognizes a more subtle benefit for nanotechnology in wireless systems. As Rung states, "There is at least one important issue where "nano" may play a role, and that is energy sources for wireless devices." He explains that while fuel-based systems like fuel cells and fuel-powered thermoelectrics have much more energy/volume than batteries, they may need to incorporate some nano-materials before they can replace batteries in wireless systems.

NANO BASICS
One company that's dedicated to the development of nanotechnology-enabled systems is Nanosys, Inc. (www.nanosysinc.com). So far, these systems include zero- and one-dimensional nanometer-scale materials as their principal elements, such as nanowires, nanotubes, and nanodots (quantum dots). Nanowires are the basic building blocks of molecular-scale electronics. Their presence in design architectures and components will enable potential breakthroughs in the performance, speed, and power reduction of electronic devices.

HP Labs, for example, already created electronic circuits made from a single layer of molecules. The molecules were sandwiched between two lines of nanowires that were just a few atoms wide (FIG. 1). The circuit was made by a perpendicular crossing of two sets of nanowires. The molecules trapped between the wires at the intersection formed a current-flow-regulating switch. When certain rare-earth metals were added to the molecular filling, a diode was formed. As with microscale electronics, the diode constitutes the basis of all Boolean expressions needed for computing-oriented nano-scale devices. While HP is in the process of making simple nanowire-based ICs, it will be many years before such components reach the marketplace.