[Engineering Feature]
Nanotechnology: The Next Revolution To Redefine Electronics
Working with atoms, molecules, and quantum effects from the bottom up, researchers are hot on the trail of self-assembling, precise, adaptable, and affordable nanosystems.
LOOKING AT NANOTECHNOLOGY'S FUTURE All of these developments bode well for nanotechnology, which is receiving record levels of funding from governments, industry, and academic circles (see "Funding for Nanotechnology Skyrockets," p. 56).
At a system level, most nanotechnology researchers foresee nano-scale particles that could be assembled into a world of tiny computers that can be embedded everywhere, including the human body, to improve every aspect of our lives. They're trying to harness the power of atoms and molecules to do useful work, just like trees that grow by using basic elements of light, water, and nutrients in the soil to make leaves, food, and wood. The issue of nano-assembly is receiving considerable attention at leading technical conferences, seminars, workshops, and in technical literature (see "Upcoming Nano-Assembly Technical Conferences," below).
It's not just small companies like Zyvex that are attempting to make inroads into nanotechnology. Major companies are getting into the action, too, with large budgets and R&D efforts. They include IBM, Hewlett-Packard, Intel, Motorola, NEC, Samsung, Siemens, Infineon, and Lucent Technologies. Moreover, just about every university worldwide has an aggressive nanotechnology R&D endeavor.
Broadly speaking, both mechanical and electrical properties, superior to anything known so far, are being investigated in nanotechnology. Researchers aim to improve these properties to build better materials, devices, and systems, like the self-assembly systems previously mentioned. Improved materials, catalysts, filters, fuel cells, solar cells, batteries, photonics, magnetics, sunscreen lotions, and sensor-dust networks have already been demonstrated using nanotechnology materials and devices.
Filters represent a very large area, using nanomaterials for all sorts of purification and cleaning. Nanotechnology also has potential as an alternative power source using fuel cells.
CARBON NANOTUBES One of the most fundamental materials under scrutiny is carbon nanotubes (CNTs)—in both the single- and multiwalled varieties. A third form of carbon that belongs to the fullerene family, CNTs offer very desirable properties when properly processed. They feature high surface-to-volume ratios, small size, and high sensitivity. CNTs exhibit excellent mechanical strength superior to steel, excellent mechanical stability, better thermal conductance than a diamond, very high current densities of up to 1010 A/cm2 (copper melts at 107 A/cm2), and extremely high conductivity and electrical resistance that's independent of their length. Some 100,000 Å thinner than a human hair, CNTs can be metallic or semiconducting. With such characteristics, they offer amazing possibilities for creating future nanoelectronic devices, circuits, and computers (Fig. 1).
Two main processing methods exist for making CNTs: electric-arc discharge and laser ablation. Both are difficult to combine with semiconductor processing and don't scale up well. But they're useful for those working from the bottom up like Carbon Nanotubes Inc., NEC, and Samsung.
Infineon Technologies has developed a multiwalled CVD process that doesn't use plasma enhancement. The company implemented this process to make multiwalled CNTs at lithographically defined locations and claims it's compatible with semiconductor processing.
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