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Carbon Nanotubes & Plastic Transistors

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  • RemyC
    What does this mean for the future of better motors & better batteries? From: http://www.pcmag.com/article2/0,1759,1130591,00.asp (Excerpt... much more where
    Message 1 of 1 , Apr 11, 2004
      What does this mean for the future of better motors & better batteries?

      (Excerpt... much more where those came from... RC)

      PC Magazine :: July 2003

      Materials: Carbon Nanotubes
      By Cade Metz

      It's the Clark Kent of microelectronics. In the early 1990s, scientists at
      the NEC Fundamental Research Laboratory in Tsukuba, Japan, discovered a tiny
      graphitelike structure with the most beguiling dual identity. Sometimes it's
      a metal, and sometimes it's a semiconductor. It can serve as a wire,
      transporting current from one place to another, and it can also serve as a
      transistor, using changes in current to store information.

      This microscopic structure, known as a carbon nanotube, could be the secret
      to extending Moore's Law-which predicts that the number of transistors on
      the fastest CPUs will double every 18 months-beyond the limits of today's
      silicon microprocessors (quite a feat in itself). "This is our best hope for
      the next generation of electronics," says Jie Liu, a Duke University chemist
      at the forefront of carbon nanotube research. It is also the basic building
      block for all sorts of future products, from flat-panel displays and
      long-lasting batteries to fishing poles and satellite cables (pound for
      pound, nanotubes are 10 to 100 times as strong as steel).

      AMD, IBM, and Intel will continue to improve silicon-based CPUs for at least
      another decade (see "Extreme Ultraviolet Lithography" below). But when they
      are unable to shrink silicon transistors any further, they may abandon
      silicon altogether and move on to completely new materials.

      Only 1/100,000 the thickness of a human hair yet exceedingly durable, a
      carbon nanotube is akin to graphite-a sheet of carbon atoms arranged in a
      tight honeycomb pattern. Your pencil tip consists of stack after stack of
      such microscopic sheets. Carbon nanotubes are formed when the sheets of
      atoms are rolled into cylinders. "They look a lot like hollow cigars," says
      IBM researcher Joerg Appenzeller.

      When carbon atoms assume a certain arrangement along the length of a tube,
      the nanotube behaves like a semiconductor. In a different arrangement, it
      becomes a metal. Semiconductors conduct current at certain voltages but not
      others. They are used to build transistors, in which processors store
      information. When one voltage is applied, current flows freely through the
      nanotube, and the transistor turns on. When a different voltage is applied,
      the current stops, and the transistor turns off. Metals, which conduct at
      any voltage, are used to build the wires that connect transistors.

      In theory, you could build an entire microprocessor from carbon nanotubes.
      Its parts would be far smaller-and thus far faster-than the copper wires and
      silicon transistors used today.

      Nanotubes are the by-products of various chemical reactions. Scientists can
      easily grow them on a substrate by reproducing these reactions, but they're
      struggling to arrange nanotubes in complex circuit patterns.

      Researchers are still seeking answers. "How do you control their physical
      properties? How do you grow them in the right place? How do you connect
      them?" asks Bob Gassar, director of components research at Intel. "Those are
      not trivial problems, and they may never be solved."

      Carbon nanotubes show promise for an extraordinary variety of products. IBM
      recently demonstrated a carbon nanotube that produces infrared light.
      Motorola and Samsung are working on carbon nanotubes for flat-panel
      displays. Nantero is developing nanotube-based memory. And researchers at
      the University of North Carolina have shown carbon nanotube batteries to
      hold twice as much energy as conventional batteries.

      Intel has just launched a research program on carbon nanotubes, which means
      the company believes there's a good chance they'll be used in
      production-level processors within the next ten years. A dual identity has
      its advantages.


      Microprocessors: Extreme Ultraviolet Lithography
      By Cade Metz

      The future of Moore's Law is all smoke and mirrors. Companies like AMD, IBM,
      and Intel will continue using silicon to build smaller and faster
      microprocessors for at least another ten years, but not without the help of
      extreme ultraviolet (EUV) lithography, a new way of printing circuit
      patterns onto silicon that eschews lasers and lenses in favor of xenon gas
      and microscopic reflectors.

      Tried-and-true optical lithography techniques that print patterns with
      features as narrow as 65 nanometers will extend Moore's Law into 2007. Only
      EUV can stretch it into the next decade, shaving feature widths to 32

      When Moore made his seminal prediction in 1965, microprocessors were built
      with essentially the same optical lithography techniques used today, which
      rely on lasers and lenses to print circuit patterns onto silicon wafers. A
      laser shines ultraviolet light onto a mask-a tiny cutout of the pattern
      being printed-and as the light shines through the mask, it conforms to the
      pattern. Tiny glass lenses then reduce its wavelength.

      To build smaller and smaller circuits, manufacturers have improved the
      precision of the laser and lenses, reducing the wavelength of the light
      hitting the wafer. Equipment used to build the Intel Pentium 4 and the AMD
      Athlon produces an ultraviolet light with a wavelength of 248 nm, printing
      circuit patterns with features around 130 nm wide. Later this year, Intel
      will move to a 193-nm optical system.

      But optical lithography will soon reach its limit. "You run into severe
      materials problems when you drop below 193-nm wavelengths," says Gregg
      Gallatin, an IBM researcher. In order to develop a 157-nm optical system,
      which will debut in 2007, scientists had to construct lenses from entirely
      new materials. Glass wouldn't work. "When you get down to 157 nm, you have
      to use a single-crystal material called calcium fluoride," says Gallatin.
      "And it was a lot harder and took a lot longer to grow calcium fluoride with
      the required optical quality than people expected." Building lasers and
      lenses capable of wavelengths below 157 nm proved impossible.

      Researchers sought out alternative forms of lithography, eventually settling
      on EUV. Rather than using a laser as a light source, an EUV system produces
      ultraviolet light by electrically exciting xenon gas. To hone the light, it
      uses specialized mirrors instead of lenses. By reflecting the light off
      these microscopic mirrors, the system narrows wavelengths to about 13 nm.

      The EUV LLC Consortium, an Intel-led group that includes AMD, IBM, Infineon,
      Micron Technology, and Motorola, hopes to debut EUV around 2009, shrinking
      CPU feature widths to around 32 nm. But the technology needs fine-tuning.
      "It's still not clear that this will be a cost-effective solution," says
      Gallatin. "EUV has the technical capability, but it may cost a horrendous
      amount of money to put into production."

      Intel Fellow Peter Silverman is confident that the technology will launch as
      scheduled. "EUV will be affordable for leading-edge companies," he says.
      "You don't need a lot of tools for the first generation, and there's time to
      get the cost down for the second generation." Chances are, Moore's Law will
      reach its golden anniversary.


      Materials: Plastic Transistors
      By Cade Metz

      That famous line from The Graduate isn't as ridiculous as it once was.
      Today, plastics are the future of the $30 billion computer display market,
      and they may even lead to new breeds of computer memory and microprocessors.
      Within five years, companies like DuPont and Xerox will begin using
      plastics, in conjunction with organic light-emitting diode technology (see
      "OLED Displays" below) and organic transistors, to build flexible displays.
      Eventually, plastics could be used to build entire machines that you can
      bend and drop without breaking. "These devices will be so flexible and light
      that we'll be able to integrate them directly onto almost any type of matter
      we want, including a piece of clothing," says Beng Ong, a research fellow
      and manager of the printed organic electronics group at the Xerox Research
      Centre in Mississauga, Ontario.

      Silicon transistors-the engines of microprocessors, displays, and memory
      modules-are fast and effective, but manufacturers must build them on flat,
      rigid materials. The extreme heat required to etch circuits in silicon would
      melt any sort of flexible material. That's why you never see curved LCDs,
      and you can't twist your laptop. Recently, scientists at Bell Labs and Xerox
      have found ways of using organic materials rather than silicon to build
      electronics. Such materials can be manipulated at room temperature, which
      would let manufacturers build devices on flexible plastic.

      One well-known example is the OLED, but researchers have also found ways of
      fashioning full-fledged transistors from organic materials. Like OLEDs,
      organic transistors could be used in plastic displays within five years and
      in electronic paper within a decade. If scientists can make them fast
      enough, plastic memory and microprocessors could be next.

      Such plastic devices will not only be supple, they'll be resilient. "You
      won't have to worry about dropping your Palm Pilot or sitting on it," says
      Cherie Kagan, an IBM researcher who's worked on plastic electronics for the
      past five years. And they may be even cheaper than silicon-based devices.

      Manufacturing silicon requires not only high temperatures but also
      clean-room and vacuum environments. Scientists hope to manufacture plastic
      devices easily under ordinary conditions. In December, Ong and his team of
      Xerox scientists announced that they had produced an organic transistor that
      retains its performance even when exposed to oxygen.

      Eventually, plastics will enable true wearable computing: Not only displays
      but entire systems could one day be woven into our clothes. Are you
      listening, Benjamin Braddock?


      Materials: OLED Displays
      By Carol Levin

      When Kodak researcher Ching Tang noticed a green glow from some organic
      material he was experimenting with at his lab in 1985, he discovered
      something big. He had just invented an organic light-emitting diode (OLED),
      launching an industry expected to reach over $3 billion by the end of this

      Simply put, an OLED uses a carbon-based designer molecule that emits light
      when an electric current passes through it. Piece lots of molecules together
      and you've got a superthin display of stunning quality-no power-draining
      backlight required. Conveniently, OLED displays can be produced in the same
      way an ink jet printer sprays ink onto a sheet of paper, making
      manufacturing cheap and simple.

      But here's the real clincher: OLEDs can be printed onto flexible plastic.
      Sheets of them could be easily produced, opening a new universe for product
      designers, from displays that roll up to ones that are woven onto clothing.
      (See "Plastic Transistors".)

      In anticipation of this future, a flurry of business and scientific activity
      is under way. The technology is being perfected (blue emitters in particular
      are stubborn), and OLED intellectual property is hotter than ever. "Every
      major player is a licensee of Kodak or Cambridge Display Technology," says
      Kimberly Allen, director of technology and strategic research at
      iSuppli/Stanford Resources.

      Given the endless possibilities of plastic displays, DuPont-Kodak's primary
      competitor-recently launched its DuPont Displays division and its Olight
      brand to bring OLEDs to the people the way it has brought Lycra and Teflon.
      And it's working closely with Universal Display Corp., a major patent

      In partnership with RiTdisplay Corp., DuPont has a giant production facility
      in Hsinchu, Taiwan, that's already turning out OLED displays. Ultimately,
      DuPont expects to use roll-to-roll manufacturing to create plastic displays
      by the mile.

      OLEDs have distinct advantages over existing LCD flat panels in brightness,
      power efficiency (10:1 by some estimates), viewing angle, and refresh rate
      (making them great for video). And they've come a long way since the 1980s,
      when the glow from an OLED would fade after 10 minutes. Scientists are still
      working to make OLEDs even more energy-efficient so they don't drain
      notebook and PDA batteries.

      But products are the ultimate goal. OLEDs will show up initially in cell
      phones and digital cameras; the new Kodak EasyShare LS633 has one. And once
      manufacturing yields improve (around 2005), they'll appear in glass
      flat-panel displays. Sony already has a prototype 10-inch notebook display
      (see the Prototype Gallery on this page), but volume shipments won't start
      until 2009. The transition to plastic displays is three to five years out.
      And with some patience, we'll eventually see those roll-up displays.

      In the near term, the challenge is getting a deep-blue emitter. "We're
      closing in on that rapidly," says Dalen Keys, chief technology officer for
      DuPont Displays. There's nothing like a little healthy competition to
      accelerate technology.


      Broadband: Silicon Photonics
      By Davis D. Janowski

      Chuck Yeager broke the sound barrier in October 1947, and soon after,
      everyone wanted to fly fast. But it was almost another decade before
      commercial jet traffic really took off. Then jetliners weren't fast enough,
      and the race to construct supersonic airliners began. The problem was-and
      still is-that no one could make an airline based on supersonic travel
      financially viable.

      Our relationship with the Internet is much the same. The backbone-the fat,
      fiber-optic pipes that form a mesh of light-wave traffic connecting almost
      every metropolitan network worldwide-is plenty fast enough and has bandwidth
      to spare, yet we all clamor for faster connections. We are actually
      hankering for faster connections between our homes and that speedy
      backbone-a distance known as the last mile. But getting there has been
      prohibitively costly.

      One of many technologies poised to make super-high-speed Internet access as
      well as voice and video services a reality is silicon photonics. Chips built
      with it would carry light-based traffic rather than electronic traffic-and
      photons are faster than electrons.

      Today, a handful of new home developments around the country have
      fiber-optic lines installed underground, supplying each home with a 40-Mbps
      pipe for an Internet connection, streaming audio and video, and Voice over
      IP services. That blows away cable's 1.5-Mbps top speed.

      But such systems are expensive and bulky, taking up space in the central
      office (CO). That's where the all-optical Internet backbone ends for most
      folks. COs are windowless cinder-block buildings, often just off the beaten
      path, that house banks of analog and digital voice switches. But the COs
      don't have space for the new equipment from manufacturers like Alcatel and
      Cisco Systems, and phone companies don't have the resources to drive

      Before high-speed links emerge on a wide scale, manufacturers need to
      miniaturize the equipment and reduce the costs of the optical-or more often,
      hybrid optoelectrical-hardware. That's where integrated
      photonics-specifically the integrated optical circuit (IOC)-comes in. An IOC
      is a chip with a light source, optical filters, photodetectors, and optical
      wave guides.

      Companies such as Avanex, Cidra Corp., NeoPhotonics, and others are vying to
      bring IOCs to market, but the scientific challenges loom large. "The problem
      with integrated photonics right now is that we are about where we were in
      the 1940s with the integrated circuit," explains Kumar N. Sivarajan, CEO of
      Tejas Networks. "We need a few key breakthroughs that would do for
      integrated photonics what the transistor did for integrated circuits and

      While the payoff could ultimately be substantial, it all really depends on
      the economy. The companies most heavily involved in R & D-generally smaller
      businesses that sell to the giants-are in a fragile fiscal state. "Right now
      there's just not a lot of demand. It will take those folks farther up the
      food chain to recognize a market materializing among providers and carriers
      for delivering services," says Marlene Bourne, a senior analyst for research
      firm In-Stat/MDR.

      Perhaps some help from the economy could quicken the pace and bring the
      extraordinary potential of silicon photonics right to our doorsteps-sooner
      rather than later.


      Components: Magnetic Memory
      By Cade Metz

      It's happened more times than you care to remember. You're sitting at your
      PC, putting the final period on that four-page e-mail, and your foot catches
      the system's power cord, yanking it from the socket. The e-mail is lost
      forever, and before you can start retyping it, you have to wait several
      minutes for the machine to boot, cursing yourself as Windows lets out that
      lingering chime.

      Such horror stories could soon be a thing of the past, thanks to
      magnetoresistive random access memory, or MRAM for short. By the middle of
      the decade, manufacturers expect to start building PCs with MRAM. If an MRAM
      computer loses power, you can restart it in an instant, and when you do,
      that four-page e-mail will be right where you left it.

      Today's PCs use SRAM (static RAM) and DRAM (dynamic RAM), both known as
      volatile memory. They can store information only if they have power. DRAM is
      a series of capacitors that store information as electrical charges. A
      charged capacitor represents a 1, and an uncharged capacitor represents a 0.

      To retain a 1, you must constantly feed the capacitor with power. "The
      charges you put into a capacitor are constantly leaking out," says Chia-Ling
      Chien, a professor of physics in the Krieger School of Arts and Sciences at
      Johns Hopkins University, whose research has long focused on magnetic
      structures. "Several thousand times a second, you have to replenish them, or
      they go away."

      That's why when you pull the plug on your PC, everything stored in memory
      vanishes. Work that hasn't been saved to your hard drive can never be
      retrieved. And when you turn the system back on, it has to reload the entire
      operating system.

      Gestating in research labs for decades, MRAM stores bits as magnetic
      polarities rather than electrical charges. MRAM bits are made from
      magnetized metal material. When a bit's polarity points in one direction, it
      holds a 1. When its polarity points in another direction, it holds a 0. The
      bits need electricity to change polarities but not to maintain them. MRAM is
      nonvolatile, so when you turn off the power, all the bits retain their 1's
      and 0's.

      "If MRAM replaces DRAM, then you don't have to worry when your computer
      crashes and you haven't saved what you're working on to your hard drive,"
      says Chien. "Everything stays in memory." And you don't have to reload the
      operating system, which stays in memory, letting you restart your system

      MRAM will probably debut around 2004. In June 2002, Motorola demonstrated
      the first 1-megabit MRAM chip. Hewlett-Packard and IBM are also working on
      the technology. But it could be a while before MRAM is in every PC, because
      manufacturers are set up to build DRAM, and replacing the infrastructure
      takes time and money. "Any time you move away from pure silicon, there are
      going to be problems that are very difficult to get past," says Jim Handy,
      an analyst with market research firm Semico Research. He says MRAM won't
      replace DRAM for another 10 to 20 years.

      MRAM could let developers reinvent other parts of a PC as well. Potentially
      much faster than the continuous magnetic media inside today's hard drives,
      it may lead to better mass storage devices. And it may be the catalyst for a
      new breed of microprocessor that PC manufacturers can customize. "Today,
      every AND gate, every OR gate, is burned onto a processor and can't be
      changed," says Chien, referring to a chip's logic architecture. "The hope is
      that MRAM will one day be mature enough for programmable logic, so you could
      build two identical chips and later reconfigure them to do completely
      different things."

      But that's just icing on the cake. The real news is that you won't have to
      worry about your feet catching that power cord.


      Recycling: Reverse Engineering
      By Alan Cohen

      We're good at recycling old soda cans, but when it comes to old PCs, our
      work is cut out for us. Over the next three years, 250 million computers are
      expected to become obsolete, according to the Environmental Protection
      Agency. That's good news for PC manufacturers but bad news for the
      environment. The problem: Old PCs can quickly become harmful PCs. A typical
      computer monitor, for example, contains between 2 and 4 pounds of lead,
      which can leach into the groundwater in a landfill.

      The technology to recycle PCs exists. Facilities in Ohio and Pennsylvania
      can reprocess the lead-laden glass in old computer monitors into glass for
      new monitors. Metal can be extracted from old chips, and plastics can be
      reused. Often, however, there is little incentive to do any of this.
      Consumers balk at the cost of shipping junked systems to recycling
      facilities. Manufacturers balk at taking on the responsibility of disposing
      of systems they sold years ago (something manufacturers in Europe and Japan
      already have to do). It's no surprise then that 85 percent of the 63 million
      computers taken out of service in the U.S. last year wound up in landfills,
      according to the National Safety Council.

      The challenge isn't so much how to recycle PCs but how to make PC recycling
      economically viable. It's a challenge that a team of researchers at the
      Georgia Institute of Technology has taken up. "If we can figure out a way to
      plan these systems so that they are economically sound, they will happen,"
      says Jane Ammons, Georgia Tech's professor of industrial and systems
      engineering, who runs the project along with Matthew Realff, associate
      professor of chemical engineering.

      The goal of the Georgia Tech project is to home in on optimal reverse
      production systems-recycling infrastructures that reclaim as much of a used
      device as possible at the lowest cost possible. The team has developed
      mathematical models that evaluate existing recycling facilities, including
      collection centers, glass-reprocessing plants, and smelting facilities. Such
      models will determine the most efficient ways to use the facilities and help
      researchers figure out the right combination of collection fees, tax breaks,
      and additional reprocessing facilities.

      Mathematical models have long been used to simulate systems, from airfoil
      designs to presidential elections, but the difficulty in simulating
      recycling is that the data is extremely uncertain. How many people will
      participate in recycling? How many of the computers will be resalable? How
      will participation be affected by recycling fees?

      Ammons and Realff have a range of answers, extrapolated from surveys and the
      experiences of the limited collection and recycling programs already under
      way. Analyzing all the possible what-ifs requires some heavy-duty math and
      major CPU time.

      Within the next year, the team hopes to show the Georgia legislature some
      recycling options-whether the state should impose a landfill ban or a
      disposal fee, make collections mandatory, or encourage the opening of local
      glass-reprocessing facilities. The ultimate goal is to make the system
      available for any state or entrepreneur interested in setting up a recycling
      program. Such a system should be available within five years.

      By then the computers that made it possible will be ready for the junkyard
      themselves. With a little luck-and a lot of math-they'll never get there.

      Copyright (c) 2004 Ziff Davis Media Inc. All Rights Reserved.
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