1997 Annual Report: Materials Science and Engineering

Materials Science and Engineering

Eric E. Hellstrom (Chair)
276 Materials Science and Engineering Building
1509 University Avenue
Madison, WI 53706-1595

Tel: 608/262-3732
Fax: 608/262-8353
hellstrom@engr.wisc.edu
www.engr.wisc.edu/mse

Probing the atom: New microscope to help advance semiconductor technology

Atom by Atom

In order for engineers to push semiconductor technology to the limit, they must first have a better understanding of how atoms work together. A new low-energy electron microscope (LEEM) -- one of only a few in the world -- is helping Professor Max G. Lagally's research group expand this base of atomic knowledge. Set up in fall 1996, the LEEM is being used to study semiconductor surfaces such as gallium nitride, silicon, and silicon/germanium alloys. While most surface imaging techniques require some form of scanning, the LEEM uses a static electron beam, which is ideal for real-time imaging, with an on-line video system. Additionally, the LEEM is faster and offers a larger field of view (generally 4-20 micrometers) than a scanning tunneling microscope. LEEMs are commonly used for studying dynamic surface processes such as phase transitions, epitaxial growth, chemisorption, desorption and sublimation. The microscope was purchased through a grant from the National Science Foundation, the Office of Naval Research and the Air Force Office of Scientific Research. Working with Lagally (center) are graduate student Jeff Maxson (right) and postdoctoral researcher Peter Sutter (56K JPG).

New tool developed by materials researchers makes indent in surface science studies

Much of Associate Professor Donald S. Stone's research focuses on indentation testing, the process of characterizing how resistant a material is to deformation. This is generally done by "poking" the material with an indenter tool made of diamond or another extremely hard material and checking the size of the impression. For materials such as nanolayer composites--which can be even less than a micrometer in thickness (about 1/100th of a human hair)--extremely precise measurement and placement techniques are necessary. Recently, under Stone's guidance, graduate student Karl Yoder built the world's first "nano-indenter" capable of operating at conditions other than room temperature. This first-of-its-kind device will greatly improve the ability to characterize thin films and conduct scientific studies exploring the mechanical properties of surfaces and surface layers under varying conditions, says Stone. He is currently using the tool to study strengthening mechanisms in nanolayer composites. For the indents in these materials to be seen, they must be viewed at magnifications of 30,000 to 40,000 X. Ultimately, these studies could lead to a better understanding of how to grow new and improved materials, says Stone. The thin films he studies are integral to the production of such products as microelectronics, magnetic recording devices, wear-resistant coatings and micromachines.

Vehicle could `pick up' Ghana's economy

CyclePaths, a student engineering organization under the direction of Professor Thomas F. Kelly, has built a human-powered "pick-up truck" that could potentially replace hauling items on one's head as a primary means of transporting goods in Ghana. This would greatly improve the West African republic's transportation efficiency. The idea for the vehicle came from General Motors engineer Robert Tette, a native of Ghana, who saw the original members of Cyclepaths building a bike frame at Engineering EXPO '95. Soon after, the student group enthusiastically accepted Tette's challenge of producing a light, affordable, efficient and easy-to-maintain human-powered vehicle. The finished product, which was displayed at EXPO '97, has an all-steel frame made from a 20-foot tube. The truck resembles a three-wheeled chariot with a wide front bench and a 4-by-6-foot bed. With two people pedaling, it can haul about 1,000 pounds. Even with a load of only 500 pounds, two people would be able to do the work of 40, notes Kelly. Tette was very pleased with the students' work, Kelly adds. "He wants to start a company in Ghana that would produce these, along with regular bikes."

Materials science building receives facelift

By the end of 1997, the Materials Science & Engineering Building will have taken on an entirely new look. The renovation project, which began more than a year ago, involves remodeling 76 percent of the previous facility and adding on 7,000 square feet. An enclosed, elevated walkway will connect the facility to the Engineering Research Building (ERB). "Over the years, more and more of the building has become outmoded for modern materials research," explains the department chair, Professor Eric E. Hellstrom. "We will now have fantastic new classrooms, modern optical microscopy facilities, and close proximity to the microscopes in the Materials Science Center," says Hellstrom. Five electron microscopes from the eleventh floor of the ERB, and the high-resolution transmission electron microscope currently located in the Geology Building, will be moved to Materials Science Center ground-level rooms specifically designed to eliminate electromagnetic fields and vibrations.

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Date created: 2-Oct-1997

1997 Annual Report Contents