First steps into the wonderful, if tiny, world of nanoscience
By Rick Peterson
Lawrence Today magazine, Spring 2005
Armed with needle-nose pliers, a wire cutter, and the concentration of a
surgeon, Matt Stackpole, ’05, stands in the surface-physics laboratory
of Youngchild Hall, eyeing the slightest wisp of platinum/iridium wire. Taking
full advantage of the soft metal’s ductility, Stackpole drags and snips
the end of the wire in one continuous motion in hopes of producing “a
perfect tip.” In this case, perfect would be a cut so precise, the
ultimate point of the wire consists of a single atom.
The
wire is an integral component in a scanning tunneling microscope (STM), a
small but highly sophisticated piece of equipment that “sees” an
object, not optically but by measuring minute changes in electrical currents
passing through the gap between the tip of the wire and the surface of the
material being examined — a process known as quantum tunneling. The
result (pictured, right) is a computer-generated picture of the individual
atoms on the surface of the scanned material. The more precise the wire tip,
the
crisper
the image
resolution.
“It’s basically a roll of the dice,” Stackpole says, philosophically,
of his attempts at getting a useable, much less perfect, tip. “Some
days I try for hours to get a really good one. Even with practice, it’s
a 50-50 proposition.”
With a good tip in place, Stackpole watches the STM scan a razor-thin slice
of graphite. The instrument reveals an eerie, other-worldly moonscape of
varying shades of orange, black, and white that represents the carbon atoms
of the graphite surface.
Welcome to the weird and unimaginably tiny world of nanotechnology, a place
where “buckyballs” reside, matter often behaves bizarrely, and
scientists study materials on a scale so small, a human hair in comparison
would be the equivalent width of a football field. Where size is measured
in increments comparable to the length a human fingernail grows in one second.
With the support of a $100,000 grant from the National Science Foundation’s
Nanotechnology Undergraduate Education program — one of only six that
the program awarded to liberal arts colleges — Lawrence has waded into
the scientific waters of the super-small, launching a nanoscience
and nanotechnology initiative designed to incorporate more nanoscale science into the introductory
curriculum.
Nanotechnology is not a discipline by itself but rather an interdisciplinarian’s
dream come true, a natural intersection of numerous fields of study. Since
the program’s debut in the spring of 2003, nanoscale research has been
integrated into seven Lawrence courses in chemistry, physics, biochemistry,
and biology, engaging more than 250 students. In addition, the new intermediate-level
course Nanoscience and Nanotechnology (N & N), team-taught by Assistant
Professors of Chemistry Karen Nordell and David Hall and Associate Professor
of Physics Jeffrey Collett, was offered for the first time this year, attracting
ten students from four disciplines.
In March 2004, Lawrence showcased its budding N & N program by hosting
a Pew Midstates Consortium
workshop for faculty members representing physical
science, engineering, mathematics, and computer science programs from the
14 consortium-member campuses as well as non-consortium institutions in Wisconsin.
“Lawrence
is one of only a handful of liberal arts colleges aggressively incorporating
nanoscience into a broad base of first- and second-year science
courses,” says
Nordell (pictured, left, with Richard Amankwah, ’06, and a scanning
electron microscope), the driving force behind the nanoscience initiative. “Lawrence
is clearly out in front on this. I am contacted frequently by colleagues
at peer institutions asking about our proposal, our coursework, and our equipment.
They see us as a model for starting their own programs.”
As a scientific melting pot of biology, chemistry, physics, and materials
science, among others, nanotechnology, Hall believes, is a subject tailor-made
for an institution with Lawrence’s vision.
“The research interests of our faculty and the educational philosophy
of Lawrence make nanotechnology a perfect fit for us,” says Hall, a
biochemist with a special interest in viruses. “It is becoming all
the more essential to have a broad background in the natural sciences, especially
chemistry,
biology, and physics, because the unifying level between these disciplines
lies at the nano scale. The introduction of nanoscience here has already
made me think about how I can ask new and different questions in my own specialty.”
According to Nordell, the three-member team-taught N & N course grew
naturally from the fact that many of the most interesting nanoscience questions
require contributors with varying specialties and expertise, all communicating
and collaborating together.
“Our students need to be prepared to work in teams with colleagues
from a wide range of disciplines, in the sciences and beyond,” she
says. “Through
the Nanoscience and Nanotechnology course, we try to help them appreciate
these challenges — as well as the benefits — by modeling the
interdisciplinary approach in the classroom and the laboratory.”
The term “nanotechnology” is a relatively recent one — Tokyo
Science University professor Norio Taniguchi is widely credited with coining
the word in 1974 — but the concept of nanoscale science is hardly a
new phenomenon. In his 1905 doctoral thesis, Albert Einstein first estimated
the diameter of a sugar molecule at one nanometer — one billionth of
a meter! A half-century later, in his seminal lecture “There’s
Plenty of Room at the Bottom,” Cornell University physicist and future
Nobel Prize winner Richard Feynman predicted the direct manipulation of atoms
through the use of small-scale tools. The 1981 invention of the scanning
tunneling microscope by Gerd Binnig and Heinrich Rohrer at IBM’s Zurich
Research Labs and the invention of the atomic-force microscope five years
later, affirmed Feynman’s vision, making it possible not only to record
images of individual atoms but to actually move single atoms around.
The support of the NSF/NUE grant and additional funding from the W. M. Keck
Foundation have enabled Lawrence to build a surface-physics laboratory, complete
with four scanning tunneling microscopes as well as one atomic force microscope.
The capabilities of the suite of scanning-probe microscopy instruments to
image and manipulate individual atoms “on” or “in” a
surface have substantially accelerated the development of new nanotechnologies
here and have been utilized by students and faculty across the natural sciences,
not just in physics.
Beyond equipment purchases, the NSF nanotechnology grant has provided summer
research opportunities for as many as five students. Stackpole was among
the first students allowed to “test drive” the high-tech instruments,
spending part of the summer of 2003 looking at fractal surface growth of
gold, bismuth, and graphite samples. Among his discoveries: the STMs are
so sensitive, even slight vibrations caused by people simply walking down
the hallway outside the lab can cause enough damage to the wire tip to affect
its scanning ability.
“At one point, I was able to generate an image that was better than
any of the images depicted in the user’s manual that came with the
microscopes,” says
the physics and mathematics major from Monroe, Wis. “I was pretty proud
of that.”
By the end of his summer research position, Stackpole had written an owner’s
manual specific to Lawrence’s microscopes, detailing for future users
some procedures on how to best utilize the equipment.
Upon his graduation this June, Stackpole plans to pursue graduate studies
in mathematics, specifically differential geometry, the math behind quantum
physics and string theory. Examining graphite samples may not be in his future,
but he says confidently, “I will be the guy deriving the equations
that will make it possible for scientists to look at things smaller than
graphite.”
While Stackpole isn’t completely abandoning his physics education,
nationally many students are. The late 1990s and early 2000s saw a decline
in the number of domestic students in graduate science programs. Physicist
Collett sees the emergence of undergraduate nanotechnology programs like
Lawrence’s as one way to help stem that tide.
“One
of the objectives of our NSF/NUE grant is to use nanoscience as an agent
to attract talented students in pursuit of scientific graduate opportunities,” says
Collett (pictured, right, with Matt Stackpole). “Nanotechnology itself
is not a fundamental part of the core curriculum the way thermal dynamics
or
quantum
mechanics
is,
but
it
is a
contemporary field that uses those fundamental principles.
“Nanotechnology is really more the sizzle than the steak,” Collett
adds, “but
by bringing in something that is a bit more applied and contemporary, we
are hoping to motivate students to go through the hard work necessary to
master the core of the discipline. We are initiating programs like this to
keep talented students from leaking out of the pipeline.”
As an agent for undergraduate scientific excitement, Lawrence’s venture
into nanotechnology is indeed proving good things do come in ultra-small
packages.