In the Laboratory
nsf highlights
edited by
projects supported by the NSF division of undergraduate education
Susan H. Hixson National Science Foundation Arlington, VA 22230
Curtis T. Sears, Jr.
Multidisciplinary Scanning Probe Microscopy Laboratory
Georgia State University Atlanta, GA 30303
William S. Glaunsinger,* B. L. Ramakrishna, Antonio A. Garcia, and Vincent Pizziconi Department of Chemistry, Arizona State University, Tempe, AZ 85287-1604
The new scanning probe microscopies, and especially scanning tunneling microscopy (STM) and atomic force microscopy (AFM), have captured the interest of the science and engineering communities. Since Binnig and Rohrer received the Nobel Prize in Physics for inventing STM (1) and the first commercial instruments became available in 1986, the number of publications in the new field of scanning probe microscopy (SPM) has increased exponentially. This dramatic growth is an indication that scanning probe techniques are becoming more widely accepted as powerful tools for investigating the structures and properties of materials in chemistry, physics, biology, geology, materials science, and engineering. Because of its ultrahigh resolution capabilities and options of imaging in vacuum, air, and solution, SPM has become an increasingly popular research method that is now beginning to emerge as a quality control tool in industry. Since these microscopes are rather inexpensive tabletop instruments and are relatively easy to operate, they are ideally suited for undergraduate laboratories. These instruments provide students with an unparalleled opportunity to interactively learn about and visualize surfaces and surface properties at resolutions down to the atomic scale. Although SPM methods have been largely limited to professional researchers and graduate students, there is increasing interest in introducing this technique at the undergraduate level (2, 3). We have developed the first multidisciplinary SPM laboratory course for undergraduate students using research-grade instrumentation to demonstrate that this field is mature and established enough to migrate from the graduate to the undergraduate level. The primary goal of this project is to create a unique multidisciplinary SPM undergraduate laboratory course using affordable, state-of-the-art instrumentation. Our experience is that the incredible potential of this relatively simple technique, coupled with its high visual impact, immediately captures and maintains student interest. The SPM laboratory course is designed to serve as a magnet to bring together students from different disciplines and ethnic backgrounds and to help prepare them for the imminent revolution in nanoscience, engineering, and technology. The new SPM laboratory is located in the modern Goldwater Center for Science and Engineering Technology at Arizona State University (ASU). It contains four SPM workstations, each of which accommodates two students who work as a team on each experiment. Thus each laboratory session has a maximum of eight students. The SPM laboratory course consists of one 50-minute class per week and one four-hour laboratory session. Labo-
ratory sessions are offered twice per week, so that up to 16 students can enroll per semester. This course is offered as an elective upper-division undergraduate laboratory in all science and engineering departments. Classes are taught by faculty having expertise in the subject area of the experiment. The class period is used to provide background information for the laboratory experiments, a broader perspective of the subject matter, including current and potential applications, and a forum for discussion and cooperative learning. The latter activity includes student teams answering questions posed by the instructor and sharing the results of their experiments. The laboratory part of the course is divided into three major units: Fundamental Principles, Core Experiments, and Special Projects. The goal of the first unit is to provide students with a working knowledge of SPM that is sufficient to perform routine experiments. The objective of the second is to illustrate several important applications SPM, while expanding the students’ operational capabilities. The third provides students with the opportunity to perform short-term research investigations of their choice under the direction of a research mentor. The principles taught include instrument operation; surface structure, defects, modification, and engineering; adsorption and characterization of materials on surfaces; surface chemical reactions; and nanofabrication. The laboratory experiments that have been developed involve surfaces (ideal and real surfaces and surface modifications and engineering), materials on surfaces (adsorption and interaction, molecular characterization, and self-assembly), chemical reactions, and biological structures. To date, students have completed several projects on a variety of materials, including thin films, microelectronics, polymers, long-chain alkanes, particulates, carotenoids, DNA, and biological cells and plaque. In summary, the NSF Leadership Projects in Laboratory Development Program has provided faculty members from both science and engineering departments at ASU with the opportunity to develop a unique multidisciplinary undergraduate laboratory course in SPM: one of the most revolutionary approaches to investigating the structures and properties of materials in the last decade. The simplicity and flexibility of the SPM method, coupled with the low cost of SPM instrumentation, combine to make the proposed course not only feasible at ASU but also at other educational institutions. We hope this course will serve as a national model for academic institutions interested in teaching this exciting subject to upper-division undergraduate students.
*Corresponding author. E-mail:
[email protected].
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In the Laboratory Acknowledgment
Literature Cited
This project has been supported by SPM laboratory development and instrumentation grants from the National Science Foundation (DUE-9451480, DUE-9451497, and DUE-9551558), Digital Instruments, and Arizona State University.
1. Binnig, G.; Rohrer, H.; Gerber, C.; Weibel, E. Phys. Rev. Lett. 1982, 49, 57. 2. Brown, R. D. J. Chem. Educ. 1992, 69, A90. 3. Coury, L. A., Jr.; Johnson, M.; Murphy, T. J. J. Chem. Educ. 1995, 72, 1088.
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