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Cover Story

August 10, 2009
Volume 87, Number 32
pp. 12 - 17

Nanotech Toolkit

As nanotechnology R&D advances, instrumentation is keeping stride with scientific and educational needs

Ann M. Thayer

CLOSE LOOK: Beaverton Health & Science High School students in Oregon use FEI’s Phenom electron microscope. FEI
CLOSE LOOK Beaverton Health & Science High School students in Oregon use FEI’s Phenom electron microscope.
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Asylum Research’s Cypher atomic force microscope.
Asylum Research’s Cypher atomic force microscope.
Asylum Research
Agilent’s 5420 atomic force microscope.
Agilent’s 5420 atomic force microscope.
TABLETOP TIPS: A researcher adjusts Nanosurf’s modular easyScan 2 scanning probe microscope. Nanosurf
TABLETOP TIPS A researcher adjusts Nanosurf’s modular easyScan 2 scanning probe microscope.
NanoSight’s particle tracking microscope attachment. NanoSight
NanoSight’s particle tracking microscope attachment.
NanoInk’s NLP 2000 dip-pen lithography unit.
NanoInk’s NLP 2000 dip-pen lithography unit.

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Nanotechnology wouldn’t exist as we know it without the instrumentation to characterize materials. Indeed, mass spectrometry uncovered the fingerprint to identify fullerenes about 25 years ago. For nanotech researchers today, believing is seeing, although they may take for granted their ability to visualize nanoscale matter.

College graduates in 2009, for instance, have never lived in a world without the atomic force microscope (AFM) and likely are not surprised by three-dimensional images of nanotubes or their university logos spelled out in DNA. First built in 1986, AFMs, along with other scanning probe microscopes (SPMs), have become critical tools for measurements and manipulations at the nanoscale.

According to instrument suppliers, nanotech researchers still desire cutting-edge technologies, and industry is starting to look for easy-to-use and robust instruments for metrology work and quality control in manufacturing. Moreover, educators want tools they can use to train students for a nanotech-savvy workforce that, according to National Science Foundation estimates, will need to be 2 million strong by 2015 to support nanotech-related industries.

Nanotechnology and instrumentation have been growing up together, and many widely used tools have emerged from the research lab. At the same time, many large instrument suppliers have developed product lines targeting nanotech R&D by acquiring small technology firms.

Although some sectors are more prosperous than others, the overall nanotech research tools market is growing at single-digit rates, Lux Research analyst Jurron Bradley says. “There’s not a whole lot of change compared with the early heydays of nanotechnology when a lot of people needed instruments,” he says. The boom years were around 2001, when the start of the National Nanotechnology Initiative helped expand programs and equip facilities.

In 1999, work on single-molecule force measurements was taking off, and a team of scientists founded Santa Barbara, Calif.-based Asylum Research. They came from Digital Instruments after it was acquired by Veeco, which then bought Thermo’s and IBM’s AFM businesses and remains a major provider of metrology and process equipment to the electronics industry.

Asylum wanted to maintain a spirit of innovation and invention, founder and Chief Executive Officer Jason Cleveland says. Six months after its formation, the firm debuted its first molecular force probe for biophysics research and has since added other SPM products. “We focus exclusively on AFMs for the high-end R&D market,” Cleveland says, emphasizing technology development and product support by Ph.D.-level staff.

In late 2008, Asylum launched the Cypher AFM. While other providers were tweaking older systems or focusing on AFMs that could handle large samples, such as semiconductor wafers, Asylum designed Cypher from the ground up for faster scanning, more accurate positional control, and the highest resolution possible on small samples, says Monteith G. Heaton, Asylum’s executive vice president for marketing and business development.

Speed is a limiting factor for AFMs. To scan faster, Cypher’s probe-holding cantilevers, at less than 10 μm, are an order of magnitude shorter than typical ones. Response to Cypher has been “phenomenal,” Heaton says, but the privately owned company doesn’t give sales figures. With operations around the world, Asylum employs about 60 people.

Cleveland anticipates further growth from moves to couple AFM and advanced optical and other microscopy techniques, as well as advances in SPM detection methods, such as piezoresponse force microscopy for studying ferro- and piezoelectric materials. Contrary to predictions a few years ago that the AFM market would become saturated, “there’s been steady growth,” he says. “Academic researchers are interested in pushing out in new directions and so they always want new instruments with new capabilities.”

Market researchers, including Lux and BBC Research, estimate that annual sales of instruments to characterize, visualize, and manipulate nanomaterials are between $1 billion and $2 billion. Although the recession has hurt sales, especially to the electronics industry, life sciences applications are gaining ground. Government stimulus money for R&D infrastructure, workforce, and educational needs is expected to give the nanotech tool market another boost.

In the AFM area, with upward of 20 competitors, the big companies usually offer products ranging from large sample systems to high-precision research units costing a few hundred thousand dollars to more affordable introductory models, explains Craig Wall, a product manager for AFMs and nanoindenters (nanomechanical testing products) at Agilent Technologies. Small firms tend to have niche technologies or applications around which they’ll sell a limited number of instruments per year.

Supplying research, industrial, and educational markets, Agilent built its AFM business via acquisitions. In 2005, it bought Molecular Imaging, an Arizona State University spin-off making AFMs and other SPMs. Purchasing part of MTS Systems in Oak Ridge, Tenn., added nanomechanical products in 2008. This year, Agilent acquired Pacific Nanotechnology, a 12-year-old AFM maker in Santa Clara, Calif.

“There is a growing need to train lab technicians who are familiar with synthesizing, handling, and characterizing carbon nanotubes.”

Agilent’s most recent AFM is the 5420, based on its 5400 model but engineered with lower noise electronics and better visual optics. The company says it is an easy-to-use tool for materials, polymer, and general surface characterization and has targeted its use in the lab—or the classroom, as Agilent and many of its competitors are doing these days. Teachers can use the 5420 to introduce students to AFM techniques through an undergraduate course curriculum and samples that Agilent provides, Wall says.

To make the 5420 affordable, it doesn’t have a lot of bells and whistles. “Environmental and temperature control and other advanced features on our flagship instrument would really be underutilized in a teaching or small university lab,” Wall explains. AFMs, in general, are convenient because they can work under ambient conditions and don’t require extensive sample preparation.

Education has always been a focus of Nanosurf, a 1997 spin-off of the University of Basel, in Switzerland. Fulfilling a secondary school teacher’s request, the three scientist founders constructed an easy-to-use scanning tunneling microscope (STM) for teaching purposes, says Robert Sum, one of the founders and now head of marketing. Because research-grade STMs are too complex for the classroom, they envisioned a compact version that Sum describes as “a ‘coffee table’ STM that could be hooked up to a laptop computer and give you atomic resolution in 15 minutes.”

To create this simpler and less expensive system, Nanosurf’s founders capitalized on three innovations: thin-film piezos that need very low voltages for scanning; a stepping motor designed to be robust yet controllable in 20- to 50-nm steps; and internal electronics that manage data acquisition, interface easily, and leave only data display to the laptop.

That basic STM, which sells for about $10,000, has evolved into the modular easyScan 2. Like most SPM systems, easyScan2 can readily operate with an STM or AFM scan head, as well as other accessories, to extend its capabilities. For example, the FlexAFM head, which uses flexure electromagnetic scanner technology, lets the system conduct fast, linear scans of samples in air or under liquids for a range of applications. Nanosurf also sells the only battery-powered mobile AFM, Sum adds.

Competitors making dedicated systems for the educational market, and not just selling downgraded research equipment, have come and gone, Sum says. A challenge has been to have a simply designed unit that’s robust enough to survive in student labs at a cost an institution can afford, he explains. “And the learning curve must be quite quick because they’ll have to perform a measurement in an afternoon.”

Others targeting Nanosurf’s niche are Beijing Nano-Instruments, which positions itself as a low-cost provider. Russia’s NT-MDT has the Nanoeducator SPM line. Ambios Technology, which acquired Quesant Instruments in 2006, offers the Q-Scope series AFMs for academic research.

Nanosurf opened a U.S. subsidiary in 2008 and has grown to 28 people. The company plans to manufacture its 1,000th teaching STM this year and has built more than 2,000 instruments overall. “Our strategy has always been to grow with the market,” Sum says, or what’s amounted to about 15% per year.

Ease-of-use, portability, robustness, and low power consumption were specifications that a Swiss-led consortium considered when choosing Nanosurf’s technology for an instrument that traveled on the Phoenix Mars Lander. Scientists at Swiss universities in Basel and Neuchâtel also were on the team that built the microscope. Operated remotely with a two-day lag between command and operation, the instrument took the first AFM image of martian dust in July 2008.

Most nanoscale materials under study can be found much closer to home. Besides inspecting materials, an AFM tip can also deposit substances, as first reported in 1995. For the past eight years, Skokie, Ill.-based NanoInk has commercialized dip-pen nanolithography (DPN) licensed from Northwestern University.

With features as small as 14 nm, DPN can generate patterns using arrays of pens and “inks”—such as nanoparticles, biomolecules, small molecules, and polymers—on a range of substrates. In the first six months of this year, NanoInk has seen interest in its technology rise substantially, says Dean Hart, executive vice president.

NanoInk’s bench-top DPN instrument, provided since 2003, is the Nscriptor, which incorporates a commercial AFM system for imaging results. Earlier this year, the firm introduced two new systems. The research-focused DPN 5000 expands on the combined AFM and nanopatterning capabilities. The desktop NLP 2000 is a simple-to-use and more affordable unit, without the complexity of an AFM, for making larger nanoarrays over areas as big as 40 by 40 mm, such as petri dishes and microscope slides.

NLP 2000 is the core of NanoInk’s NanoProfessor Project, launched in March. Along with the DPN unit, the complete $300,000 package includes a fluorescence microscope and an AFM for imaging, consumables, and a semester curriculum for about 25–30 students. For subsequent semesters, the only additional expense is for the consumables. “We’re trying to keep that in the range of $10,000 for a semester,” Hart says.

The developing curriculum will introduce students to chemistry, biology, and physics at the nanoscale, Hart says. The first program will go live in September at Dakota County Technical College, near Minneapolis. Eventually, he says, “our goal is to build a full two-year program.” To support participating schools, NanoInk is offering promotional materials and sponsoring scholarships, a mentorship program, and an educational forum for students, educators, and researchers.

According to NanoInk’s research, at least 100 colleges and schools around the U.S. have nanotech programs, but Hart believes that the extent to which they provide hands-on experience is limited. In addition, most students are at graduate-level research institutions that have the requisite tools. To create a broad-based nanotech workforce, he adds, community colleges, technical schools, and even high schools will need access to more affordable capabilities to prepare students.

DPN competes with AFMs adapted for nanofabrication, as well as nanopatterning technologies such as photolithography, electron-beam (e-beam) lithography, and nanoimprint lithography. Start-ups such as Molecular Imprints in Texas, New Jersey-based Nanonex, and Sweden’s Obducat have been advancing nanoimprinting, mostly through industrial and manufacturing tools they sell.

Meanwhile, e-beam lithography and related electron microscopy are the purview of larger firms, such as Hitachi, JEOL, Carl Zeiss, SII NanoTechnology, and FEI. Although electron microscopes have high resolving power, their operation usually calls for more involved sample preparation and working under a vacuum. The price tags also can be high, ranging from a few hundred thousand into the millions of dollars.

FEI supplies scanning and transmission electron microscopes, and ion- and e-beam (or dual-beam) instruments to the research, electronics, life sciences, and industrial markets. “The research division is about 40% of our business, and it’s had very nice growth over the past five years, while life sciences is our most rapidly growing market space,” says Michael R. Scheinfein, FEI’s chief technology officer. “We’re also seeing lots of activity in new areas as nanotech spreads to smaller economies.”

In recent years, FEI has launched new instruments in all its market areas, ranging from sophisticated, high-resolution research systems to robust automated industrial equipment. It has also developed an easy-to-use desktop scanning electron microscope (SEM) called Phenom, which is accessible to universities, colleges, and high schools at $65,000 to $80,000, Scheinfein says. With 30-nm resolution and up to 24,000× magnification, it fills price and performance gaps between optical scopes and high-end SEMs.

Sample loading is one feature that differentiates Phenom from competing scaled-down SEMs, explains Paul Scagnetti, FEI vice president and industry division general manager. Instead of a large vacuum chamber, only a small sample cup has to be evacuated. The system also scans the entire sample, and through a touch-screen interface, the user can choose where to look closer. “In analogy to cameras, it’s a ‘point and shoot,’ ” he says. Remote control is possible as well.

Designed for the nonspecialist, Phenom allows most people to get their first image in less than 20 minutes, Scagnetti says. FEI is partnering with other organizations to develop coursework for the Phenom. Like any supplier, the company has a vested interested in creating new users, Scagnetti admits. “On the one hand, it’s a business, but the aspiration also has been to enable people to learn more about nanotechnology,” he says.

In another twist on optical microscopy, Bob Carr, founder and chief technical officer of NanoSight, in England, came to believe that he could “see” nanoparticles back when he worked in a government lab. Trying to detect extremely small particles in complex backgrounds, he found that with a specially configured and finely focused laser beam, he could view nanoparticles in a liquid under an optical microscope of relatively modest magnification.

“It’s the equivalent of seeing motes of dust in a shaft of sunlight in a dark room,” Carr says. “We don’t actually image the particles. We can’t see what shape they are, what they look like, or what they are made of, but depending on the way in which they move, we can tell you what size they are.” From videos of the moving particles, the size distribution can be calculated from their Brownian motion.

Created in 2004, NanoSight sells systems consisting of a microscope, laser-based optical illumination module, camera, computer, and nanoparticle tracking analysis (NTA) software for $40,000, including installation, training, and support. Growing from three to 15 people and with new offices in the U.S., the firm has sold about 200 systems worldwide since 2006. Customers including pharmaceutical and chemical companies still use the systems largely as R&D tools and not yet for quality control.

“To our knowledge, nobody does what we do in the way we do it,” Carr says about his technology. Discounting high-resolution AFMs or electron microscopes as too sophisticated for the job, Carr says the nearest competing method is dynamic light scattering (DLS), which also is more expensive but considered the “gold standard” method. “DLS is very fast, very reproducible, and very accurate when you have a well-behaved monodispersed, nonaggregated sample,” he explains. In comparison, NTA gives size information on heterogeneous samples in less than a minute. These days, Carr believes, a lower priced technology is also attractive.

To be able to see particles, NTA works only in a defined concentration range. In addition, it can’t detect particles that are too small or don’t scatter enough light because of their refractive index. For modest-refractive-index materials, Carr says the minimum detectable size is about 20–40 nm; without the NTA module, only 500- to 1,000-nm particles would be visible with the same microscope. Looking ahead, Carr says, “we are working on variations on our basic instrument to give two-to-four independent parameters per particle simultaneously.”

Like Carr, Rice University professor R. Bruce Weisman has commercialized work from his lab. In 2002, he and Sergei M. Bachilo, in collaboration with Richard Smalley’s group, deciphered the complex near-infrared emission spectrum of single-walled carbon nanotubes in terms of all the structural forms (based on diameter and chiral angle) in a sample. “This information is very hard to find by other methods, but it can be important to know which are present and in what amounts,” Weisman says.

“The aspiration has been to enable people to learn more about nanotechnology.”

They published their analysis, but the method didn’t catch on as Weisman had anticipated. “I realized that one of the keys was making the process simpler, so people didn’t feel they had to be specialists,” he says. After building a prototype automated analyzer and making unsuccessful contact with instrument firms, he decided in 2005 to start up Applied NanoFluorescence (ANF) in Houston. Financed by Weisman and his wife, the now-self-sustaining firm sold its first unit to DuPont in 2005 and has placed about 20 others at companies, research centers, and universities, where at least one has been used in undergraduate labs.

ANF’s NS1 NanoSpectralyzer lists for about $79,000. Weisman constructs the optical system, and CTO Bachilo handles the computer interface and software. A part-time worker does some assembly, and the company has a full-time vice president of business operations, as well as international distributors.

This spring, ANF launched the NS2, which can measure the near-IR fluorescence, visible, near-IR absorption, and Raman spectra of a bulk sample to provide information on diameter distribution, concentration, aggregation, metallic content, and chemical derivatization of nanotubes.

“Characterization is essential,” Weisman says, because researchers need to understand the composition and quality of their samples to get consistent results when determining physical, chemical, or toxicological properties. Because of their high sensitivity, ANF’s instruments can detect trace quantities of nanotubes in biological tissues and environmental samples as well.

Although the spectroscopic measurements are relatively conventional, it’s the integrated and automated analysis of the raw data that makes NS1 a powerful research tool yet suitable for routine use, Weisman says. A competitor’s spectrofluorometer does a full 2-D scan across excitation and emission wavelengths, he explains, but by sampling just three excitation wavelengths, the ANF machines can collect and analyze data more rapidly. “We have substituted a lot of spectroscopic knowledge and modeling for brute-force data collection,” he says.

Weisman seems content with operating ANF as a “cottage industry” and focusing on his first career as an academic scientist. “The idea was not to be a huge corporate success so much as to develop this technology and make it available to people in the nanotube community.”

With a similar “do-it-yourself” attitude, Dennis J. Flood acquired the technology for making high-quality, multiwalled carbon nanotubes (MWNTs) from the NASA Glenn Research Center, in Cleveland, that had been developed while he worked there as head of space photovoltaic R&D. “The group got really frustrated trying to buy anything that was worth anything to experiment with and decided to try to make their own nanotubes,” he explains. Large commercial producers, targeting composites and other markets, often don’t make ones of sufficient quality or aren’t interested in supplying small amounts, he says.

In 2006, Flood and his son Dennis M. Flood founded Nanotech Innovations (NTI) in Oberlin, Ohio. The company has since turned the NASA group’s injection chemical vapor deposition process into a benchtop apparatus that can fit into a fume hood and can make research-scale quantities (a few tenths of a gram) of high-quality MWNT within a few hours. Their SSP-354 has a list price of $25,000. Having optimized the process, NTI supplies solutions of the patent-pending organometallic precursor and other consumables.

A user injects the solution into a two-zone furnace where iron catalyst particles are formed. Once growth is catalyzed, the nanotubes form on the surface of a quartz tube, which is later removed to collect the material. “Under typical operating conditions, we have seen less than 3% catalyst content by weight and greater than 90% purity,” Dennis M. Flood says. The nanotubes average about 50 nm in diameter and can be anywhere from several to a few hundred micrometers long, depending on the operating parameters. For users who don’t have the capabilities for characterizing nanotubes, NTI will analyze three samples for free to verify the process.

“Most processes for growing carbon nanotubes require a two-step process where you have to prepattern a substrate with a catalyst, whereas ours doesn’t require that,” the younger Flood explains. He believes that NTI is the only company making a low-priced compact system that can give researchers a reliable and accessible source of nanotubes. Once the equipment is amortized, he claims, the cost of producing nanotubes with the SSP-354 is competitive at less than $10 per gram.

The Wright Center for Photovoltaics Innovation & Commercialization, in Ohio, is using an SSP-354, as is the lab of Rice professor Andrew R. Barron, who serves on NIT’s science advisory board. “We are looking to sell our system not only to large universities but also to two- and four-year colleges that are the training ground for tomorrow’s nanotechnology workforce,” Flood says. “There is a growing need to train lab technicians who are familiar with synthesizing, handling, and characterizing carbon nanotubes.”

Looking ahead, instrument suppliers, whether small or large, see change coming. As nanotechnology continues to move from the research lab into industrial application, tools will be needed not only for characterization in manufacturing but also to address health, safety, and environmental concerns. As tools migrate in that direction, suppliers believe there could be another big upswing in instrumentation sales.

“It’s going to require a shift in philosophy because it is one thing to build a tool to do very sophisticated scientific research, but that’s not the right tool for the process engineer, the production engineer, or the chemical technician,” Agilent’s Wall says. “Fundamentally, it may still be an AFM or STM or particle analyzer, but its embodiment and how the user interacts with it will be quite different.”

Chemical & Engineering News
ISSN 0009-2347
Copyright © 2011 American Chemical Society
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