Ever smaller and ever faster. The pursuit of nanotechnology—chips, sensors, pumps, gears, lasers, novel materials, and an unending assortment of other useful “things” with features on the scale between one-billionth of a meter (about 10 hydrogen atoms across) and 100-billionths of a meter—is driving science and engineering to extremes.

Consider work under way at the National Institute of Standards and Technology (NIST), where research truly is pushing the limits of technology. Here, scientists and engineers are building atom and electron counters, single-photon turnstiles, ultracold ion and atom traps, and lasers that generate uniform pulses of light that last only a few trillionths of a second.

For NIST, the quest to design, manipulate, manufacture, and assemble at the molecular and atomic levels translates into a full agenda of demanding measurement jobs and related tasks.

Already, more than 1,700 companies in 34 nations reportedly are pursuing the commercial promise of nanotechnology. Mastery of the almost infinitesimally small, however, will require an underlying technical foundation. Just like gage blocks (standardized sets of hardened steel blocks of accurately determined thicknesses) and other widely adopted measurement tools that enabled the rise of mass production and interchangeable parts, exceedingly accurate measurement tools and other underpinning generic technologies will be essential to realizing the anticipated bounty of nanotechnology products and services.

NIST role

Researchers in NIST’s seven major laboratories are developing measurements, standards, and data crucial to private industry’s development of products for a nanotechnology market that could reach $1 trillion during the next decade. NIST’s work also aids federal agencies’ efforts to exploit nanotechnology to further their missions, such as national security and environmental protection. These technical contributions are in addition to NIST’s funding support for U.S. industry’s nanotechnology development work.

• NIST and the National Nanotechnology Initiative
• Fundamental science and basic measurement capabilities
• Characterization of nanostructured materials
• Nanoscale electronics, optoelectronics, and magnetics
• Nanochemistry and nanobiotechnology
• Quantum computing and communications
• Specialized nanotechnology facilities and capabilities
• "What's Your Nano IQ?" (a fun quiz)
  

NIST and the National Nanotechnology Initiative

As the nation’s premier measurement laboratory, NIST is a key contributor to the National Nanotechnology Initiative (NNI), a long-term federal effort to speed the advance of the emerging fields of nanoscale science, engineering, and technology. In 2002, NIST funding for nanotechnology-related projects in the NIST laboratories totaled almost $40 million.

Development of instrumentation and standards—essential building blocks of a nanotechnology infrastructure—is one of the NNI’s top priorities. NIST leads efforts to address two of the NNI’s “Grand Challenges”: one on instrumentation and metrology (measurement science) and, with the National Science Foundation, one on manufacturing processes. It also contributes significantly to work on materials, electronics and optoelectronics, and elements of other initiative grand challenges.

In all these areas, measurement advances are key to achieving the understanding needed to harness nanoscale properties and quantum phenomena. Likewise, new measurement tools enable the process and control capabilities necessary for cost-effective production of high-quality nanotechnology products.

For fiscal year 2004, the President has requested a funding increase of $5.2 million to further NIST’s nanotechnology efforts. The President also has proposed an additional $3 million to accelerate and intensify NIST’s globally recognized work in quantum information science. This work aims to exploit the peculiar quantum behavior of molecules, atoms, and subatomic particles and to pave the way for enormously powerful quantum computers and perfectly secure communications systems.

Even before nanotechnology became a buzzword, NIST scientists and engineers were moving to address the inevitable need to measure and control processes at molecular levels. The scale and pace of these efforts have grown in response to increasing industrial and scientific demand. As a result, NIST’s penchant for precision and accuracy must rise to new levels. After all, when working in the nanoscale realm, pinpoint accuracy only gets you in the general neighborhood, a hair’s breadth is a cavernous space, and a split second might as well be an eon.

United by a focus on measurements, data, and standards, nanotechnology efforts in the NIST laboratories reach well beyond current capabilities, all the way into the fuzzy, probabilistic realm of quantum mechanics. Laboratory projects cut across five important areas, as explained below.

Fundamental science and basic measurement capabilities

Although every industry has unique priorities, some basic technology needs transcend business sectors and fields of technology. In support of many industries aiming for nanotechnology products and services, NIST is helping to advance fundamental understanding of the properties and performance of matter from the “bottom up”—at the level of atoms and molecules.

The agency also is responding to this and other shared needs by developing measurement references that are based on unchanging natural phenomena: quantum processes and fundamental constants. This work will lead to extremely accurate universal measurement standards that could be realized anywhere—without the aid of material artifacts.

Indeed, many industries—established and those in the making—will require higher-resolution measurements of length, time, force, mass, and chemical composition that correspond to the molecular and atomic scales of nanotechnology. Complementary efforts aim to develop and “harden” capabilities for precisely manipulating and assembling the basic building blocks of nanotechnology products.

Sample highlights

For example, NIST scientists and engineers have:

• Pioneered laser-based methods for trapping and cooling atoms and ions to within the minuscule fractions of absolute zero. This capability has paved the way for detailed studies of the particles’ quantum behavior and for technologies aiming to exploit this behavior.
  
  
• Created, with a University of Colorado colleague, the first Bose-Einstein Condensate (BEC), a supercooled collection of atoms that coalesces into the equivalent of a single “super atom.” The BEC has enabled development of prototype atom lasers, and it is a critical component of several approaches to building a quantum computer.
  
  
• Helped to broaden the utility and versatility of atom optics—the use of beams of laser light to focus and deposit atoms. The basic technique can be used to create regularly repeating nanometer-sized wires and other metallic structures, as first demonstrated by NIST scientists in the early 1990s. Using two lasers that emit light of different wavelengths, Dutch and NIST scientists recently created two super-imposed nanoscale arrays of ultrathin chromium lines that interfered with each other in the same way that light or sound waves of different frequencies go in and out of phase, increasing and then decreasing in intensity. The result was a set of chromium lines with both a fine periodicity of 213 nanometers and a coarse periodicity of 40 micrometers. The technique could be used to fabricate a single patterned measurement reference for calibrating and checking the accuracy of microscopes with resolutions ranging from less than a nanometer to micrometers—from scanning probe microscopes to optical microscopes.
  
  
• Devised a method for synchronizing and phase-combining the beams of two different lasers to create a new coherent beam of light. The accomplishment, once considered beyond reach, provides a flexible method for controlling ultrafast pulses of light. In turn, such lasers can be used to control individual atoms and molecules and to “freeze frame” events that transpire in trillionths of a second.
  
  
• Developed the world’s most accurate electron counter—a device in which single electrons are pumped through nanoscale tunnel junctions by gate electrodes. The counter can place 100 million electrons—one at a time—on a capacitor with an uncertainty of less than one electron. The work will lead to improved (and, perhaps, portable) standards for measuring capacitance and current, two important electrical quantities. Single-electron transistors with extraordinary charge sensitivity (one thousandth of an electron charge) also have been developed. These transistors may be used for reading the output signals of solid-state quantum computers and for detecting the motion of individual molecules. Also in the works at NIST: a device that can dispense individual “Cooper pairs”—pairs of electrons that are the fundamental charge carriers in superconducting materials. Cooper pair devices will operate faster than single-electron devices and also may be used for quantum computing applications.
  
  
• Led the way in developing ultra-accurate direct and alternating current voltage standards based on superconducting quantum devices. These devices—Josephson junctions—produce predictable quantum steps in voltage by sending a current through layers of superconducting metal sandwiched between normally conducting metal. Recently, NIST researchers succeeded in increasing the quality and voltage output of the devices by densely stacking junctions in three dimensions. Superconducting and normal metal films in the devices are only 20 to 30 nanometers thick and require precise sub-nanometer control for optimal operation.
  
  
• Demonstrated a method for directly measuring the reaction-diffusion front profile in a photo-lithographic structure. This profile defines the position and shape of nanoscale structures, with nanometer resolution. This technique will enable the creation of nanometer-scale structures with more sharply defined features, needed to fabricate smaller, faster devices of all types.
  
  
• Pioneered a widely used technique for writing nanometer-sized features on metal, semiconductor, and insulating surfaces. With the method, called scanned probe oxidation, researchers use scanning probe microscopes to build functional structures, devices, and ultraminiature systems on a variety of technologically important surfaces.
  
  
• Demonstrated a tightly controlled, repeatable method for writing features with dimensions as small as 10 nanometers on silicon surfaces, a capability expected to deliver new measurement references for manufacturing nanometer-scale devices.
  
  
• Built a laser interferometer—a widely used instrument for precision measurements—that can measure picometer (trillionth of meter) distances that are smaller than the diameter of a single atom.
  
  
• Built an experimental electrostatic force balance, the trial version of a technology intended to measure nanonewton forces—akin to the strength of a single chemical bond that couples two atoms in a molecule.
  
  
• Patented (in late 2002) two high-accuracy, high-precision positioners. The innovations show promise for meeting the needs of exacting manufacturing processes that will require minuscule workpieces to be maneuvered and placed with nanometer-level accuracy. Initially intended for assembly and alignment of optoelectronic devices, NIST’s new planar and six-degrees-of-freedom micropositioners are configured to screen out or compensate for most sources of positioning errors. A next-generation version is being considered for an ultrahigh-precision job on an interstellar explorer, a future spacecraft being designed at Johns Hopkins University/Applied Physics Laboratory. As envisioned, the enhanced device would position a lens that steers a laser beam communication link toward Earth from locations many billions of miles away in outer space.
  

Characterization of nanostructured materials

Emerging capabilities to combine disparate atoms and molecules, to tinker with molecular structure, and to maximize properties by exploiting peculiar quantum behaviors have created a smorgasbord of tantalizing opportunities. Nanoscale alterations and additions make it possible to create tailor-made materials optimized for specific uses—from new insulators for integrated circuits to superior stealth coatings for military aircraft to superior-performing, biologically compatible materials for implanted biomedical devices.

Up to 100 times stronger than steel, carbon nanotubes are an area of especially intense interest. Discovered in the early 1990s, the nanometer-sized cylinders of carbon already are being eyed for electronic, automotive, aerospace, and a variety of other applications.

To speed progress, NIST is developing new nanometer-resolution probes of the properties and three-dimensional atomic arrangements of nano-structured materials. NIST also is building a collection of high-speed screening methods that permit designers to evaluate the strengths and weaknesses of their creations.

Sample highlights

Institute scientists recently:

• Helped to develop a straightforward method for creating self-organizing, highly ordered arrays of semiconducting “nanocolumns”—a new class of liquid crystalline materials that, observers say, could open the way to new low-cost, lightweight displays and electronic devices. (Collaboration with University of Pennsylvania)
  
  
• Reported (Jan. 13, 2003) a new hybrid type of soft X-ray spectroscopy that speeds up chemical analyses of experimental nanostructured films and surfaces. The technique—called combinatorial near-edge X-ray absorption fine structure spectroscopy—provides the equivalent of a camera that can shoot both still photographs and movies. It can be used to reveal chemical bonds and the orientations of surface molecules and to capture the dynamics of surface reactions. This new capability could speed the development of films with tunable surface properties and other types of custom-made nanomaterials.
  
  
• Began building a “nano-tribometer,” an apparatus capable of measuring frictional and other forces at the nanometer scale and comparing the forces from nanometer to millimeter scales of measurement. Accurate and reliable measurements of these forces are critical to the design and performance of nanometer-sized devices and systems incorporating these devices.
  
  
• Found that dispersing a tiny amount of carbon nanotubes into polypropylene—a popular plastic used in automobiles, packaging, toys, furniture, housewares, textiles, and numerous other everyday items—greatly reduces the polymer’s flammability. Accounting for just 1 percent of the resultant material’s weight, the nanotubes outperformed existing environmentally friendly flame retardants.
  
  
• Demonstrated a novel way to measure quickly the strength of thin films and coatings using a high-throughput method. This high-throughput method allows simultaneous, rapid testing of different types of materials for applications such as optical coatings, nanoelectronic structures, and nanoscale adhesives.
  
  
• Began building a “nanofluidic module,” a device capable of controlling and measuring the properties of nanoliter droplets and particles in complex mixtures. This device will allow for mixing, manipulation, processing, and measuring of nanoscale structures.
  

Nanoscale electronics, optoelectronics, and magnetics

Demand for faster, more powerful information technology will not abate. Nor will the unrelenting space crunch in data storage ease any time soon. Down the road, when current manufacturing methods are extended to their limit, nanotechnology—in the forms of molecular electronics and spintronic devices that manipulate the spins of electrons—could provide the answer to both challenges.

Besides providing chipmakers and their suppliers with essential tools to meet today’s severe process-control and quality requirements, NIST also is looking several generations beyond current integrated circuit technology. For example, a collection of molecular electronics projects has the overall aim of developing the measurement science base that will enable industry to, quite literally, make a quantum leap in the design and fabrication of electronic devices.

NIST measurement support is credited with helping the U.S. data storage industry develop more sensitive read heads that capitalize on the giant magnetoresistance (GMR) effect, discovered in the late 1980s. Exploited in commercial technology less than a decade later, the quantum phenomenon enabled the industry to continue its trend of increasing data storage capacity by more than 40 percent annually.

Ongoing NIST projects aim to extend measurement and imaging capabilities in support of industry efforts to develop more powerful and more versatile magnetic devices, such as magnetic random access memories, which retain data even when power is interrupted, and tunable spintronic microwave devices that would increase storage capacity vastly.

The NIST laboratories also help to further industry efforts to design and manufacture affordable integrated circuits that combine, on a single chip, devices that control electrons with those that manipulate light, such as lasers, filters, amplifiers, and switches. Today, photonic and electronic devices are packaged as discrete components, linked by optical fiber. Although these hybrid packages are the lifeblood of advanced telecommunication technologies, nanotechnology techniques will enable integrated optoelectronic circuits that deliver higher performance and new capabilities at a lower cost.

Since the mid-1970s, NIST has been providing measurement and related technical support to the optical communications industry. Today, work spans from characterizing the properties and performance of tailor-made photonic crystals to exploring methods for patterning periodic arrays of quantum dots, “artificial” atoms created by isolating and confining electrons in a small space. Already used in lasers, quantum dots are at the center of much innovative activity in electronics, optoelectronics, and biotechnology as well as other areas. A recent survey found 230 U.S. patents covering quantum dots and their applications.

Sample highlights

Recent developments and accomplishments include:

• Developed a prototype atomic “ruler” for calibrating dimensional measurements of 100 nanometers and below. In collaboration with International SEMATECH, NIST researchers have produced silicon reference features with almost atomically flat, vertical side-walls. An electron beam shined through thinned transverse sections of the features produces images representing individual planes of silicon atoms that can be counted. Since the spacing between silicon atom planes is known with great accuracy, this allows an ultraprecise measurement of the width of the silicon feature. These “absolute” measurements then are correlated with faster, less expensive measurements of other features of various widths determined by, for example, electrical resistance or with a scanning electron or atomic force microscopy. NIST now is transferring the technology to a commercial standards supplier.
  
  
• Developed what is, perhaps, the world’s highest-resolution energy-dispersive X-ray detector, an advance described as “truly dramatic” by the chief executive officer of the SEMATECH consortium of chipmakers. The NIST invention, which has been licensed for commercialization, enables fast and unambiguous analysis of flaws and contaminants too small to be detected with tools now used in semiconductor manufacturing. NIST researchers also are adapting the technology—a transition-edge-sensor X-ray micro-calorimeter—for nanoscale analyses of the chemical composition of a wide range of materials. They also plan to develop large arrays of microcalorimeters that could be used to track changes in materials properties as thin films are deposited on surfaces.
  
  
• Launched a program in spintronics, based at NIST’s state-of-the-art Magnetic Engineering Research Facility, one among the agency’s several collections of specialized instruments devoted to spin-polarized electron injection into semiconductors. The collaborative program will focus on the materials science metrology issues that must be resolved in order to create a new generation of microelectronics whose operation is based on the electron spin rather than the electron charge (as in conventional electronics).
  
  
• Developed a new method—X-ray porosimetry—for characterizing Swiss-cheese-like nanoporous films for use as insulators on next-generation integrated circuits. These tiny holes improve the insulation’s ability to reduce electrical interference between devices that are crowded together on chips. Along with other methods developed at NIST, this technique is helping to narrow the search for new ultrathin insulators.
  
  
• Devised and demonstrated methods for characterizing prototype devices made with experimental voltage-tunable dielectric thin films, anticipated to be the basis for faster, more versatile, and cheaper wireless communication technology. With NIST-developed measurement techniques, researchers using the Institute’s cryogenic microwave probe station can determine the properties of new materials in actual devices, rather than as unpatterned thin films.
  

Nanochemistry and nanobiotechnology

At its most basic level, nanotechnology is a matter of breaking and making chemical bonds. The expanding ability to form novel chemical relationships can result in dramatic transformations in the properties and performance of materials.

Many of the new strategies and methods for organizing and linking atoms and molecules are borrowed directly from nature. Consider, for example, cellular methods of self-assembly—sometimes called programmed chemistry—that result in proteins and organelles, the “machinery” of cells. NIST studies in the early 1990s helped to establish the feasibility of self-assembly as a means of chemical synthesis. Obtained with a unique, custom-built microscope, high-resolution images of self-assembled monolayers, a class of ultrathin organic films eyed for many applications, revealed important structural details of the films. The results also helped to explain the principles and forces that govern the process of self-assembly.

Current nanochemistry efforts range from refining NIST-developed methods for fabricating and miniaturizing components of plastic lab-on-a-chip devices to pushing beyond the limits of chemical imaging technologies. With a battery of tools now under development, NIST researchers aim for rapid detection and identification of single atoms and molecules in an area measuring one square micrometer, a huge space in the nano world.

In the long run, health care, in general, and biotechnology, in particular, may realize the largest dividends from advances in nanotechnology. Anticipated applications range from biosensors and targeted drug-release systems to tissue repair and generation. The number and types of measurements that must be made during the design, fabrication, testing, and approval of such technologies are large. Some of these measurement needs have just begun to receive attention.

Already a supplier of measurement references for DNA analyses, cholesterol tests, and a variety of other clinical tests, NIST is expanding the scope of projects devoted to helping others to innovate and to introduce nanotechnology applications that are safe and deliver substantial benefit to health-care consumers and practitioners.

A key focus area is tissue engineering, where the number of factors to be controlled or monitored is huge. For example, NIST researchers are developing genetically engineered smooth muscle cells that can help evaluate biomaterials for blood vessel stents. The cells emit fluorescent light whenever they are replicating. Ideally, these biomaterials should discourage cell replication, which tends to reclog the artery requiring the stent. By validating that the cells fluoresce consistently under controlled conditions, NIST hopes to provide a valuable tool for quickly testing which stent materials are least likely to reclog.

Sample highlights

Recent NIST accomplishments include:

• Patented in February 2003, a new chemical sensing strategy exploits the unique optical properties of nanoparticles to enhance the sensitivity and selectivity of a recently developed detector. Like all materials, nanoparticles absorb light at characteristic frequencies. Yet, the efficiency of this absorption, as determined by an “optical absorption cross-section,” can be enormous, and can be “tuned” to particular wavelengths. Nanoparticles also can be chemically modified to interact more strongly with selected molecules. These attributes can be leveraged to detect a range of target compounds and to increase the sensitivity for one or more chemical species. The newly patented approach couples the versatility and selectivity of nanoparticles with a powerful, optical resonator-based chemical detector, also developed at NIST. Nanosized particles of gold or other materials are bound to surfaces of the resonator, further increasing its sensitivity and detection capabilities. The new technology eventually could lead to miniature detectors for explosives, chemical, or biological weapons.
  
  
• Designed a novel “chemical microscope” (technically, an infrared near-field scanning optical microscope) that makes it possible to determine chemical composition in nanometer-scale regions of organic thin films, polymer composites, and other important materials.
  
  
• Developed and demonstrated a method for precise placement of nanocrystalline films on the surfaces of microscopic “hotplates,” a NIST-developed technology eyed for a variety of sensing applications. Because of their unique properties and electronic behavior, the nanostructured sensing films greatly enhance the sensitivity and utility of this combined system for chemical detection and analysis. In response measurements, the improved microhotplate sensing technology detected chemical warfare agents in concentrations as small as one part per billion.
  
  
• Built prototype nanowire sensors composed of segments of metal and an electrically conducting polymer embedded with antibodies or other compounds that bind selectively to biological or chemical agents, emitting light in the process.
  
  
• Launched a five-year project to develop new ways to measure the structure, function, and behavior of single biomolecules. A nano-biotechnology platform, now under design, will integrate nanopores, nanofluidic “pathways,” mechanical elements, and other devices for isolating, manipulating, and characterizing single biomolecules. This platform will provide an experimental staging area where single molecules can be observed and analyzed with a wide variety of tools including laser “tweezers,” magnetic beads, vibrational spectroscopy, current amplifiers, and confocal and atomic force microscopy. The goal is to collect detailed information on chemical composition, binding energies, geometric shape, and folding patterns of biomolecules in a variety of environments. Such data are critical for understanding how specific proteins work and for designing new medicines.
  
  
• Progressed on several fronts toward implementing the platform described above, including studies of a naturally occurring “nanopore,” a biomolecule that has the right size, shape, and electrical properties for “threading” individual molecules of single-stranded DNA and RNA. By monitoring the decrease in current caused by the transport of DNA through the pore, NIST researchers hope to develop a system for determining the length of DNA fragments and other structural information. Ultimately, it may be possible to use nanopores to determine the sequence of bases (A,G, C, and T) in a DNA strand. The system also may also be useful for detecting a wide range of other molecules, such as harmful chemical or biological agents.
  
  
• Started building the nation’s first neutron-beam research station fully dedicated to biological membrane research. At this new resource, located at the NIST Center for Neutron Research and funded by the National Institutes of Health, a national team of researchers will probe how cell membranes and inserted proteins are assembled, and how they can be tailored to repel attack by harmful agents and diseases, pointing the way to better vaccines and drugs.
  
  
• Built a prototype “molecular recognition force microscope” designed to map the distribution and density of biomolecules on a surface at high speed, as well as measure how strongly the molecules adhere to the surface. Antibodies or other selected chemical compounds affixed to the tip of this modified atomic force microscope will enable detection of a single molecule as it binds to a sample surface. Information gathered with the instrument will aid developers of tissue-engineered products and other implanted medical devices.
  
  
• Demonstrated a reliable method for fabricating reproducible films of collagen, the chief component of connective tissue and a key ingredient of many cell-culture studies. Because collagen has several structural forms, a standardized reference is needed to ensure that results of studies using the extracellular matrix protein—a kind of scaffolding that supports cell growth and development—can be compared. The work is part of a larger NIST effort to develop a standardized tool kit of reference materials and gene markers intended to enable rapid evaluation of prospective biomaterials for tissue-engineered products.
  
  
• Developed new measurement methods using live cells to indicate compatibility of plastics covered with nanometer-scale patterns. Such materials can foster cell growth and speed the beginnings of new tissues and organs. The field of tissue engineering promises to repair functionality destroyed by injury, disease, and aging.
  
  
• Helped to standardize what may become a new type of biomarker for cancer susceptibility. Working with the M.D. Anderson Cancer Center at the University of Texas, NIST researchers designed a standard protocol for examining breaks in chromosomes extracted from blood cells. The technique involves tagging specific regions of chromosome 5 with fluorescent DNA probes that glow red and green to help examiners identify relevant breaks. Greater numbers of such breaks may indicate a higher than average susceptibility for certain diseases such as lung cancer.
  

Quantum computing and communications

NIST has done pioneering work in laser cooling of atoms and ions, earning two of its researchers the Nobel Prize in Physics (in 1997 and 2001) and a third the 2000 International Quantum Communication Award. This work lays the foundation for quantum computing, which calls for the use of quantum bits, or qubits, instead of the familiar digital bits used in conventional computers.

Quantum computers have the potential to store and process enormous amounts of information, immensely more than can be handled by today’s computers. What are now intractable scientific and technical problems would become ripe for research and, ultimately, solution. Quantum computers could factor very large numbers, perform cryptography, and aid science in large-scale modeling projects such as first-principles simulation of materials properties. Quantum communications techniques offer greatly improved security of data communications by making covert eavesdropping physically impossible.

Sample highlights

Examples of NIST’s recent contributions to the quest for quantum computing and communications technology are:

• Building on their years of experience working with laser-cooled ions stored in electromagnetic traps, NIST scientists have demonstrated many of the basic building blocks for a quantum computer based on ion traps. For instance, NIST has demonstrated the first quantum gate for performing logic operations as well as long-duration qubit memory. Recently, a NIST researcher and colleagues from the Massachusetts Institute of Technology and the University of Michigan published a design for a quantum computer based on a large number of interconnected ion traps. This machine uses techniques already demonstrated at NIST on systems of a few traps.
  
  
• NIST scientists have demonstrated the operation of macroscopic qubits based on “artificial atoms.” These qubits consist of Josephson junctions, a superconducting technology that NIST has used to make voltage standards. Microwave signals are used to control the qubits’ macroscopic state, represented by the direction of the electrical current in the circuit. This experimental system offers the potential for coupling qubits easily using wires and capacitors, and for scaling to larger sizes using standard integrated circuit fabrication techniques.
  
  
• For quantum communications networks, which use “flying qubits” (photons), NIST scientists are pursuing two approaches to creating devices that emit single photons on demand.Scientists have demonstrated a multi-channel system for generating photons at selected frequencies, increasing the likelihood of emitting a single photon and certifying the accuracy of that photon. In addition, NIST has demonstrated single photon emission from a single semiconductor quantum dot (an electronic nanostructure that spatially confines electrons to a nanoscopic scale).
  
  
• In collaboration with Boston University, NIST has demonstrated the first quantum communications detector system that not only indicates when a photon arrives at a destination but also determines how many photons arrive simultaneously. The new detectors are based on superconducting, transition-edge-sensor, microcalorimeter technology, which absorbs the heat from incoming photons and produces an electrical signal proportional to the absorbed energy. This system offers much higher efficiency and lower noise than conventional detectors, as well as elimination of false positive results. The instrument could be used as a receiver for a quantum communications system, a calibration tool for single photon sources, and a tool for evaluating quantum communication protocols and the security of quantum cryptographic systems.
  
  
• For more on quantum computing and communications, see NIST Research on Quantum Systems for the 'Next' Information Age (fact sheet) or Quantum Information Programs at NIST (extensive Web site).
  

Specialized nanotechnology facilities and capabilities

Nanotechnology is both the means to an end—an enabler of accomplishments in a truly diverse mix of science and engineering fields—and, perhaps, the end in and of itself—a revolution in industry that will deliver wave after wave of innovative products and services.

Work under way at NIST illustrates nanotechnology’s dual nature. Many projects are leveraging capabilities to manipulate molecules, atoms, and even subatomic particles with the aim of enhancing existing services for established industries, from increasing the accuracy calibrations to developing portable measurement references that customers can use on-site. Others are addressing measurement-related challenges confronting businesses and industries still in the making.

Both sets of activities are carried out collaboratively, and both benefit from a diverse collection of facilities and equipment, some of it custom-designed and unique to NIST. Some examples follow.

Advanced Measurement Laboratory (AML)

In 2004, NIST scientists will begin moving into what will be the world’s premier all-purpose facility for measurement-related research. The 47,480-square-meter (511,070-square-foot), $235.2 million AML will give NIST and its partners in U.S. industry access to research and development capabilities not available anywhere else in the world.

Stringent controls on particulate matter, temperature, vibration, and humidity will reduce environmental “noise” to unprecedented levels, eliminating obstacles to research and services in nanoscale science and engineering.

The AML will consist of five sections: two single-floor measurement laboratory sections below ground with 151 modules (for improved vibration isolation and temperature control), two single-floor instrument laboratory sections above ground with 187 modules and one ultraclean room wing above ground. Specialty areas within the AML include 48 precision temperature control laboratories (constant temperatures within ±0.1 degree Celsius or ±0.01 degree Celsius depending on need) and 27 extremely low-vibration laboratories.

NIST Center for Neutron Research (NCNR)

A national user facility and one of the best of its kind in the world, the NCNR generates high-quality beams of neutrons, which are becoming increasingly indispensable research tools in fields ranging from biology to materials science, often in applications with high impact on future nanotechnology.

Neutrons are non-destructive, highly penetrating probes, useful for studying the structure, properties, and dynamics of materials of many types—from proteins to nanocomposite coatings. Because they behave like tiny waves of energy, neutrons also make excellent rulers. Depending on neutron temperature, the length of the neutron ruler can be tuned over a range spanning from roughly the size of a single atom to the size of a molecule composed of hundreds or thousands of atoms.

The major source of “cold” neutrons in the United States, the NCNR houses 28 experiment stations. Each year, these instruments support the research of more than 1,700 scientists and engineers from 250 universities, companies, and government laboratories.

NIST Combinatorial Methods Center

This collaborative research center is devoted to advanced state-of-the-art high-throughput methods that can accelerate development of new materials. Combinatorial methods and the supporting resources at the year-old center allow researchers to explore simultaneously—or in rapid sequence—combinations of materials characteristics and formulations on a miniaturized scale. Such methods enable researchers to evaluate quickly how composition and processing influence a material’s performance. With combinatorial tools, they can pinpoint optimal processing conditions, screen for novel properties, and build comprehensive data sets and models. The methods are well-suited to study polymer coatings and multilayers down to nanometer-scale thicknesses, such as used in microelectronic applications. Ongoing work focuses on designing and evaluating thin polymer films for enhanced nanomechanical, thermal, and UV (ultraviolet light) dependent properties. Another project focuses on approaches for screening polymers with clay, nanotube, and nanoparticle additives for improved fire resistance.

Nanoscale Physics Facility

The centerpiece of a new program to develop a solid understanding of how electrons behave in quantum-confined systems, including so-called spintronic devices, this new resource began its initial trial in late 2002. Features include a state-of-the art cryogenic scanning tunneling microscope (STM); a superconducting magnet system that can generate intense magnetic fields; a molecular beam epitaxy system for fabricating nanostructures from a variety of classes of materials; and a microscope for customized preparation of STM probes. The entire system can operate in an ultrahigh vacuum environment with automated transfer and placement of samples and STM probes.

Additionally, this facility will test the concept of the autonomous assembly of nanostructures designed to realize magnetic and electronic properties stemming from quantum phenomena. Such structures will be assembled autonomously, atom by atom, under computer control.

Molecular Measuring Machine (M³)

This NIST-conceived two-dimensional coordinate measuring machine can measure—with nanometer-level accuracy—locations, distances, and feature sizes over a 50-millimeter by 50-millimeter area, an enormous expanse in the nanotechnology world. M³ uses an STM with sub-nanometer resolution as its sensing probe and a high-precision interferometer (also with sub-nanometer resolution) to measure the probe’s position as it traverses a sample artifact.

Magnetic Engineering Research Facility

Established with the aim of advancing enabling technologies key to ultrahigh-density data storage, this laboratory is one of the world’s most elaborately instrumented facilities for preparing and evaluating magnetic thin films. It supports research ranging from the most basic to the industrially applied. Thin-film samples can be studied with the most modern surface, interface, and magnetic diagnostics at each step in the fabrication process. Properties that can be investigated include elemental composition, thickness, atomic structure, roughness, and magnetic and magnetoresistive properties. These capabilities allow researchers to establish the correlations between the film structure and properties and to use the resulting insights to control and improve the properties of device-related materials.

Pulsed Inductive Microwave Magnetometer (PIMM)

This unique NIST-developed instrument—a significant advance in technology for picosecond measurements of ultrafast magnetization switching—can accelerate the search for new materials needed for next-generation high-speed recording heads. Using PIMM, materials scientists, in their quest for novel, highly magnetic, nanostructured materials to record data in extremely small bits (at sizes below 160 square nanometers per bit), now can assess quickly the composition and growth conditions that promote high-speed response, permitting the development of future magnetic memories that read and write data at sustained speeds in excess of 1 billion bits per second. With such data rates, one could store the informational content of the Encyclopedia Britannica in little more than one minute. The battery of property data gathered with the new, highly automated magnetometer rapidly yields a comprehensive assessment of a magnetic alloy’s dynamic behavior, which determines whether a candidate material has the potential to meet the industry’s targets for increasing data storage performance.

For more information on NIST’s nanotechnology work, contact: Barbara Goldstein, (301) 975-2304; barbara.goldstein@nist.gov.