A short history of Scanning Probe Microscopy
1st-generation scanning tunneling microscope
1981-1986: Atomic resolution - really?
1981: Gerd Binnig and Heinrich Rohrer
perform tunneling in air experiment.
1982: Binnig and Rohrer combine tunneling
with scanning, creating first- and very soon second-generation
1983: First surface investigations using
STM. Many surface scientists remain sceptical.
1984: Tersoff and Hamann, and Garcia
develop theories of STM.
1985: Third-generation STM. First replications.
1986: Fourth-generation STM. Binnig &
Rohrer receive Nobel Prize in physics.
2nd-generation scanning tunneling
In the first few years after their invention, Binnig
and Rohrer encountered disbelief and even some hostility. Given
scientists' previous experience with phenomena on the atomic scale,
and especially the quantum mechanical principle of uncertainty,
the possibility of atomic resolution seemed remote if not theoretical
impossible. The doubts were allayed only with the successful replication
of STM measurements by other groups. This occurred after the development
of the fourth generation: a simple, easy-to-use, and robust instrument
that could be used not only in an ultra-high vacuum but in air
and even liquid. More detail here.
Image source: Binnig & Rohrer's
first four generations were reproduced from IBM Journal of
Research and Development, 30 (1986), 359. By permission of
IBM Technical Journals.
After the Nobel Prize many researchers began to build their own
STMs and to explore its capabilities in new fields. Binnig & Rohrer's
fourth generation instrument was comparatively simple, so that some
scientists (e.g. Erik
Lægsgaard, and Vladimir
Kirillovitch Nevolin) built one from scratch in a matter of
Variants on the original STM, such as the Atomic Force Microscope
were developed, now usually grouped under the heading of Scanning
Probe Microscopy (SPM). With all these instruments, scientists still
had to separate artifact from reality, but they no longer doubted
it could be done.
New enterprises sprang up manufacturing SPMs. Early examples include
Digital Instruments, Park
Scientific Instruments, and Hitachi
Scientific Instruments, who were all selling to the US market
by 1991. They testify to a lively market. An STM cost $30,000 to
$200,000 in 1990. By 1992, the AFM alone had become an estimated
$40 million a year business, and by mid-1993 DI claimed to have
sold more than 1,000 of its Nanoscope SPMs.
SPMs found application in ever more fields. As Ivan
Stensgaard has put it: "One
saw new phenomena almost regardless of what one studied".
The STM was operated within
electrochemical cells. Its first sibling, the AFM, could be
used to image non-conducting surfaces, such as glasses. By 1992
several investigations were under way to image biological samples,
such as viruses, bacilli, or DNA strands.
The analog feedback circuit was replaced once computers became
sufficiently fast to do the calculations. In fact, most scientific
instruments were combined with electronic systems around 1990. The
commercial SPMs were equipped with software, both guiding the scanning
process and processing/imaging the data, and they usually included
graphic workstations. This software was gradually rendered more
user-friendly, for instance by automating sample loading and operating
from a Microsoft Windows 3.1 platform (first advertised by Park
1987 - 1993:
New uses and variations
The first STM built at DFM.
Kim Carneiro points to the tip.
- SPMs in US market in 1991: R&D Magazine,
Feb 1991, p. 220
- 1990 cost of STM: ibid., August 1990,
- $40 million business: ibid., September
1992, p. 98
- DI 1993 sales: ibid., June 1993, p. 44
- SPMs used in life sciences: e.g. Horber
et al, Scanning Microscopy, 6 (1992), 919-930; Haberle
et al, Ultramicroscopy, 42-44 (1992), 1161-1167
- Analog to digital: R&D Magazine, Feb
- Graphic workstations: ibid., Aug 1990,
- Windows and Park Scientific Instrument SPM:
ibid., Sept92, p. 99
- Image source: photo of Kim Carneiro holding
DFM's first STM by Arne Hessenbruch
Early 1994 to now:
becoming a part of the furniture
J. Garnaes and a Nanoscope at DFM.
There is now an almost bewildering variety of SPMs.
For instance, by making the tip out of a ferromagnetic material,
the magnetic properties of the sample can be probed. Or by measuring
the force as a function of distance, a measure of the sample's hardness
is obtained. Using such tricks, measurable properties now include:
roughness, stiffness, electrical effects, capacitance, adhesion.
The instrument making industry developed more rugged
and user-friendly SPMs. As a result they also became usable in semiconductor
fabrication lines, where cost concerns demand a great degree of
automation. Metrology now exists on the nanoscale. Speed and sample
capacity continues to be improved upon, for instance by Calvin
Quate of Stanford University. SPMs have also become much cheaper.
NT-MDT, a Russian manufacturer,
is currently making great inroads into the SPM market, primarily
through very low prices.
Many ways were found to investigate biosamples, but
so far few biologists have accepted the technique. Significant success
has been achieved within electrochemistry, such as the development
of catalysts directly out of STM research. Furthermore, since 1995,
the STM has been deployed to develop data storage devices of very
Cf. also our History of Scanning Probe
Microscopy in Denmark.
This page was written and last updated
on 19 July 2001 by Arne Hessenbruch.