Examination of activity patterns in the literature
("bibliometrics") provides a useful set of indicators
of the development of a field. We share with you some interesting
indicators that suggest that nanotechnology is emerging --
rapidly; in multifaceted ways; and with a diverse cast of
We draw on analyses of two major databases -- INSPEC and SCI
-- the Science Citation Index.
Preliminary scans of two other electronic databases found very
few U.S. Patents explicitly mentioning nanotechnology and
roughly 10 percent as many abstracts in Engineering Index
as in INSPEC.
Searches in INSPEC
We began in INSPEC with a broadly cast search. This
identified several thousand "nano-related" items. At
that point, Chris Peterson began to help us separate out the
research more closely akin to "bottom-up"
nanotechnology. Several iterations convinced us that this is a
tough task! The result is a report distinguishing four levels of
the most restrictive search seeking bottom-up
nanotechnology research. 
Table 1 profiles
nanotechnology-related activity in INSPEC. Table 1-A offers an INSPEC
activity tally for the four levels. Column A, Nano-related, shows
that interest in various facets of nanotechnology is booming (so
much so that we limit further "nano-related"
tabulations to the 1896 abstracts appearing in 1993 and 1994.
This also shows how "hot" nano is -- the literature is
burgeoning. In contrast, Column D, Bottom-up Nano, is much more
Table 1-B shows which countries
are leading contributors to the nano literature. Note that the
USA and Japan are #1 and #2 from Bottom-up to the most
encompassing "nano-related" searches. For
"bottom-up," the total number is so small that one
should not put much stock in the implications. For interest,
Yugoslavia ranks #3 with 4 abstracts. We found it particularly
interesting to see how active China is in general nano-related
At one step finer (not shown in Table 1), one can profile
publication activity by state. For "scanning probe
nano" research (C), New York yields the most abstracts (8),
followed by Illinois (5) and Arizona (4), with California
trailing (2) . In the other three tabulations, California leads.
For "nano-related" (A), California shows 83 items,
followed by New York (57) and Illinois (42), with 6 other states
publishing 22 or more. For "nanotechnology" (B),
California (40) is followed by New York (24) and Texas (16). For
"bottom-up nano," California shows 9 with no others
publishing more than 2.
Table 1-C lists "Top
10" institutional contributors to this literature for (A)
" nano-related" and (B) "nanotechnology."
Items with affiliations linked to a given company (e.g., NEC)
from all sites (various countries) are consolidated here.
Nano-related work is coming mostly from universities, followed by
research labs, and several notable industrial firms. Again, the
prominence of certain Chinese groups is notable. Note how
different list (B) is -- testimony to the fact that
"nano" covers a considerable range of research
activities that are relatively distinct from each other. The UK
strength in B is notable. Activity in C and D is more limited and
widely dispersed. For D, "bottom-up nano," the only
institutions linked to more than a single item are:
Bodenkultur Univ, Austria (3)
Belgrade Univ, Yugoslavia (3)
Utah Univ, USA (2)
Caltech, USA (2)
Matsushita, Japan (2)
Xerox PARC (2 -- or 4 if one combines with the Inst. for
Molecular Manuf . and the Foresight Inst.).
Table 1-D profiles the
keywords (subject index terms) most frequently given in these
items. Such profiles suggest the relationship of methods and
substantive areas of inquiry. In the interest of space and
sanity, Table 1-D provides a simple cut at this based on
"Top 10" keyword cumulations for each of the four
levels , also showing how the other nano levels relate to each
The first Top 10 is for "nanotechnology." Excepting the
term "nanotechnology," excluded from the Top 10 because
it was an explicit search term, note that these are the top 10 in
Column B. Note that the emphasis is overwhelmingly on
semiconductors, with prominence to STM and AFM, presumably as
observational tools. Moving down Column B, note that the 584
"nanotechnology" items do touch lightly into other
The second Top 10 is for the "nano-related" search, of
which 8 appear here with two in the previous list (silicon and
elemental semiconductors). We interpret this broad
"nano-related" search to show strongest interest in
materials science with significant reach into semiconductors and
relatively little in general chemical and biological domains.
The third Top 10 is for "scanning-probe nano"; 4 of
this Top 10 appear in the "nanotechnology" (B) Top 10
too. Scanning-probe-based nanotechnology taps into surface and
biological domains in addition to semiconductor issues; it seems
to skirt the materials issues of (A).
Recognizing the relatively small sample, the "bottom-up
nano" profile is still striking in the extent to which it
differs from the others. Table 1-D gives its Top 10 -- distinctly
Searches in SCI
The following counts are based on a search in the Science
Citation Index, years 1986 - 1995. It duplicates the INSPEC
search (Table 1-A).
The Science Citation Index shows considerably less
technology or applied science content than does INSPEC.
Where the INSPEC search emphasizes semiconductors,
lithography, and materials science, SCI has relatively
greater coverage in areas of basic research such as microscopy,
biophysics, films, and surface sciences. SCI also is known
to have a strong emphasis on the life sciences, and therefore
more strongly highlights "bottom-up nanotechnology," as
it relates to organic chemistry, biochemistry and clinical
In addition, while there is considerable content in INSPEC
using the term "nanotechnology," in SCI,
nanotechnology is a relatively infrequent term (82 occurrences in
10 years). More common usages found in SCI that seem to
relate to nanotechnology include:
NANOCRYSTAL(s) and NANOCRYSTALLINE 1127
NANOSIZE$ and NANOSCALE$ 488
SUPRAMOLECULAR and (CHEMISTRY, ASSEMBL$, SYSTEM(s),
NANOTUBE(s) or NANOTUBULE(s) 205
In particular, "self-assembly" appears to be a rich
area of research with strong kinship to nanotechnology.
SCI offers a unique capability to track citation patterns.
That is, this database tabulates references between articles.
Impressively, 246 articles in SCI cite Drexler and his
works on nanotechnology. This number is increasing over time:
about 10 citations per year for 1987-89, about 20 per year for
1990 -92, 49 in 1993, and 88 in 1994. The top journals in which
Drexler is cited are:
Journal of Molecular Biology
Journal of the American Chemical Society
Journal of the Minerals, Metals & Materials
Proceedings of the National Academy of Science (USA)
The articles citing Drexler appear in diverse journals, led by
the following groupings:
biochemistry, organic chemistry, and genetic engineering
- accounting for about 42% of the citations to Drexler;
general interest scientific journals (such as Science
and Nature, which are typically considered to be
interdisciplinary in content) - 19% ;
chemical journals of broad coverage - 13%.
Areas of solid-state physics, computers and engineering,
together, follow in their citation of Drexler's works (17% of his
It is interesting to note that of those articles that cite
Drexler, a substantial number (44) also cite J. M. Lehn, a
prolific and Nobel-Prize winning scientist. Over the past decade
Lehn has written at least 187 articles indexed in SCI .
These articles are in the areas of supramolecular chemistry, the
directed self-assembly of molecules, and molecular devices. The
single most frequently co-cited paper with Drexler is:
Lehn, J. M. (1988), "Supramolecular Chemistry- Scope
and Perspectives: Molecules, Supermolecules, and Molecular
Devices," Angewandte Chemie - International
Edition in English, Vol. 27, p. 89-112.
Other frequently co-cited authors with Drexler include I.
Riede, D. J. Cram, B. Dietrich, and P. R. Ashton. All five of
these authors publish heavily in Angewandte Chemie, which
is notable for its absence of citations to Drexler.
In conclusion, by comparing the nanotechnology content of INSPEC
and the Science Citation Index, we see evidence of
divergent development. The results suggest substantial and
growing differences among researchers interested in the
"nanosciences." In SCI nanotechnology coverage
is less applied and more oriented towards basic research, so much
so that the word "nanotechnology" itself is only
infrequently used. Secondly, in SCI, nanotechnology
research relates much more closely to the life sciences and most
particularly to bio- and organic chemistry. "Bottom-up
nanotechnology" items in INSPEC share this
orientation. Thirdly, there is evidence that different indexing
terms are being developed in the basic and life sciences to refer
to items of research that are nonetheless nanotechnology-related.
Fourthly, distinct citation patterns are emerging where Drexler's
"big picture" of nanotechnology development is being
worked by authors performing significant and detailed work in the
emerging problems of a new discipline. Distinctive terminology is
emerging for various forms of nanotechnology research. Indeed, it
appears that "nanotechnology" research is maturing, as
indicated by the appearance of divergent research areas.
 Alan Porter is professor of Industrial & Systems
Engineering, and of Public Policy, at Georgia Tech; he also
directs the Technology Policy and Assessment Center. Scott
Cunningham is in the PhD program at the Science Policy Research
Unit (SPRU) of the University of Sussex.
 INSPEC is produced by the Institution of Electrical Engineers
(IEE). It corresponds to the three Science Abstracts
print publications: Physics Abstracts, Electrical
and Electronics Abstracts, and Computer and Control
Abstracts. As of January, 1995, INSPEC
contains 1.98 million abstracts on line, dating from 1986. About
84 percent of the source publications are in English. SCI
is produced by the Institute for Scientific Information.
 Boolean searches were performed in INSPEC.
Search abbreviations include: "adj" - adjacent to;
"and" - both terms occur; "or" - either term
occurs; "near#" - terms appear within # words of each
other; "with" - terms both appear in the same field
(e.g., abstract); "not" - the indicated terms does not
appear; "(s)" - singular or plural; $ - truncation (any
extensions). Search includes items for which the following terms
appear (in keywords, abstract, etc., not just in titles): (atomic
adj scale) near1 structure(s); (molecular adj control) near1
structure(s); nanoelec$; nanoma$; nanotechn$; nanoproc$;
nanoprob$; nanofab$; or nanostructur$.
 Search includes: [(scanning adj (tunnelling or tunneling)) or
((atomic adj force) with (microscope(s) or microscopy or
spectroscopy))] and [nanotechnology or (molecular adj
electronics) or (molecular adj (modeling or modelling or
 Search consists of: (molecular or computational) adj
nanotechnology; or molecular adj (machine(s) or manufacturing).
We attempted various other searches without notable success --
e.g., linking construction or device with STM/AFM generated items
primarily about device construction; linking deposition with
STM/AFM got predominantly to items that entailed both deposition
(e.g. , chemical vapor) and observation (e.g., STM), but rarely
STM usage for deposition of molecules.
 Searching by abstract and content fields is limited in this
database from the years 1991 to the present. Searches from the
years 1986 - 1990 are therefore based on titles only.
 "Nano-related" tabulations in Parts 1-B to 1-D are
based on only the 1896 abstracts published in 1993 and 1994.
 Countries are the "Top 10" in order of
"Nanotechnology" (Column B) frequency. "%" is
based on total abstracts for which a country of author origin is
 The "Nano-related" "Top 10" reflect only
1993 and 1994 abstracts out of 1896 (66 with no affiliation
noted). The "Nanotechnology" "Top 10 " are
based on 584 abstracts (46 with no affiliation noted).
 Shown are a compilation of the most frequent keywords. The
compilation is clustered into "Top 10" lists from each
of the levels, excluding the search terms used to construct that
level and not repeating terms appearing in the other clusters.
Values are the % of the items in which this explicit keyword
appears; for "Nano-related," the tabulation is limited
to the 1896 abstracts for 1993 and 1994. These terms are
standardized in this database. So, for instance, many related
terms could be noted -- "semiconductor technology" is
included, but "semiconductor materials" or
"semiconductor growth" are not.
STM '95, July 23-28, 1995, Snowmass Village, Colorado.
Sponsored by American Vacuum Society. Includes atomic and
molecular manipulation. Tel. 212-248-0327; fax 212-248-0245;
Advanced Surveillance Technologies, Sept. 4, 1995,
Copenhagen. Sponsored by Privacy International, Electronic
Privacy Information Center. Effects on privacy of leading edge
and coming technologies, including nanotechnology. Tel
202-544-9240; fax 202-547-5482; email email@example.com.
3rd Int'l Symposium on Atomically Controlled Surfaces and
Interfaces, Oct. 12-14, 1995, Raleigh, NC. Sponsored by
American Vacuum Society and Japan Society of Applied Physics.
Includes atomically controlled formation of nanostructures,
manipulation of atoms, self-assembling structures, but mostly
top-down, semiconductor emphasis. ACSI-3, Box 8201, Raleigh, NC,
27695; email firstname.lastname@example.org;
Nanotechnology lecture for Smithsonian, Washington, DC, by
K. Eric Drexler, date in Oct. to be announced in next Update.
42nd National Symposium of American Vacuum Society, Oct.
16-20, 1995, Minneapolis. Includes nanometer-scale science and
technology: mostly top-down but also supramolecular structures,
self assembly, proximal probe based fabrication, biological
nanostructures. Tel. 212-248-0327; fax 212-248-0245; email email@example.com.
4th Foresight Conference on Molecular Nanotechnology, Nov.
8-11, 1995, Palo Alto. Enabling science and technologies,
molecular components, systems design, R&D strategies.
Foresight Institute, tel. 415-917-1122, fax 415-917-1123, email firstname.lastname@example.org, Web
Senior Associate Gathering, Nov. 11-12, 1995, Palo Alto.
Annual meeting of Foresight, IMM, and CCIT Senior Associates
(min. pledge $250/yr for 5 yrs). Intensive exploration of
nanotechnology issues; participants need to have read Engines or
Unbounding. Accessible to non-technical participants. Foresight
Institute, tel. 415-917-1122, fax 415-917-1123, email email@example.com.