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Probing the vast potential of glass

During his 12-week summer internship at the Indian Institute of Science in Bangalore, Ray Hickey ’14 found time to visit Hogenakkal Falls, also known as the “Niagara Falls of India”…

As far back as the Stone Age, almost three million years ago, naturally occurring glass like obsidian was used to make sharp cutting tools. By around 3000 B.C. ancient peoples, perhaps in Egypt where most early glass is preserved, were creating glass beads.

Today, the easily manipulated composition of glass makes it one of the most versatile modern materials—and thus one of the most useful.

Glass is what windows, skyscrapers and mirrors are made of. It is used in your kitchen, in your car and in your computer. When used to make eyeglasses, glass can help you see what is right in front of you. When used in telescopes, it can help you see worlds tens of millions of light-years away.

Ray Hickey ’14 understands the versatility of glass: He spent the summer at the Indian Institute of Science in Bangalore, India, in a research internship sponsored by Lehigh’s International Materials Institute for New Functionality in Glass (IMI-NFG).

For Hickey, a materials science and engineering major, the internship also underscored the importance of his field.

“Many of the solutions to challenges faced by engineers,” he said, “are limited by the materials that are currently available.”

A useful sensitivity

During his 12-week stay in India, Hickey conducted research into chalcogenide glass and its electrical properties. Chalcogenide glass can be used in rewritable optical disks—such as DVDs—and random-access devices, like the RAM disks in computers, said Hickey.

Most glasses are oxide-based, meaning they are made from sand combined with oxides, including sodium oxide, calcium oxide and magnesium oxide. Chalcogenide glass is a non-oxide glass in which oxygen is replaced by another element, like selenium or sulfur.

Chalcogenide glass is sensitive to both light and electricity. Its sensitivity to electricity enables it to store more information on devices that take advantage of its electrical properties. For example, a CD that uses a brief exposure to light—a pulse—to store information is limited in how much information it can store. A laser can only focus on certain spots on a CD of a given size, and these spots are limited.

“You cannot focus a laser below the wavelength of light—one micrometer or so—whereas there is no such limit when using an electrical signal. You can store a lot more information this way,” said Hickey’s adviser, Himanshu Jain, a professor of materials science and engineering and the principle investigator for the IMI-NFG.

There are five International Materials Institutes across the United States, but Lehigh houses the only one that focuses on glass. The IMI-NFG is funded by the National Science Foundation and is a partnership with Penn State University. It supports a variety of research projects, including an eight-year effort to develop a type of glass that helps damaged human bone to regenerate.

In India, Hickey studied phase-change materials, which can be switched in a nanosecond back and forth between amorphous and crystalline states using an electrical field.

“I was doing research on phase-change memory materials, which is sort of similar in essence to what’s in a rewritable DVD,” he said.

“In the case of a DVD with optical properties, a laser reads ones or zeros in the material as it is spinning. The materials I was working on are more for the electrical side. You write data in these materials and it is saved until you purposely change it.”

This implies that phase-change memory materials have higher storage capacities than traditional memory materials. Additionally, said Hickey, “The benefits of this are that less energy is used, and it is used more efficiently.”

Chalcogenide glass may be particularly useful in the development of a mobile phone with a high storage capacity and a longer battery life.

The practical applications of materials science and engineering research attracted Hickey to Lehigh.

“I actually chose Lehigh because of the materials science department here,” he said. “I knew that I wanted to do some sort of science or engineering, and MSE is a perfect marriage of both. It deals with very fundamental aspects of matter but is grounded in technological applications as opposed to being overwhelmingly theoretical.”

The IMI-NFG is celebrating its tenth anniversary this year.

Story by Carla Prieto

Posted on Wednesday, October 02, 2013

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