Simens '06 studies carbon nanotubes with her mentor, Andrew Minor, at the National Center for Electron Microscopy.
Amanda Simens possesses a large curiosity, but she was thinking small four years ago when she searched for a university to attend.
Not only did she choose Lehigh over bigger schools in her native California, Simens also settled on a major in materials science and engineering, one of Lehigh’s smallest departments.
“I wanted to go to a school with small classes where I wouldn’t be just a number,” says Simens.
Simens wasted no time in availing herself of the ample research opportunities in the materials science and engineering department, which attracts 15-25 undergraduate majors per class.
As a sophomore, she began using the department’s electron microscopes and joined the research group of Himanshu Jain, who directs the International Materials Institute for New Functionality in Glasses (IMI-NFG) at Lehigh. The following year, Simens added a minor in nanotechnology and started a second research project, this one involving carbon nanotubes.
Along the way, Simens traveled once to Florida to present a paper and twice with Jain to the U.S. Army Research Laboratory in Maryland to meet other glass experts. She completed summer internships at the U.S. Department of Energy’s National Center for Electron Microscopy, which is part of the Lawrence Berkeley National Laboratory in Berkeley, Calif.
Last month, Simens and four other U.S. university students, including Jamie Neilson ’06, were awarded scholarships by IMI-NFG to travel to the 15th International Symposium on Non-Oxide and Optical Glasses in Bangalore, India, and present their research.
Simens gave a presentation titled “Origin of Optical Losses in Ge-Se Containing Chalcogenide waveguides: EXAFS and SEM Study,” which she prepared with Ashtosh Ganjoo, a senior research scientist in Lehigh’s Center for Optical Technologies.
Simens had asked Ganjoo a year earlier to help her examine glasses at the nanoscale to determine their optical properties. Ganjoo helped Simens analyze the results she acquired using Scanning Electron Microscopy (SEM) and Extended X-ray Absorption Fine Structure. EXAFS is a technique that reveals the bonding of atoms in glass. After studying three germanium-based glasses, Simens and Ganjoo concluded that the structure of the glass was related to its optical properties.
“Lehigh has resources,” says Simens, “and the faculty and staff go out of their way to help you. They invite students to picnics in the summer and banquets in the winter. They welcome you and make the effort to get to know you.
“It’s harder at bigger schools to get this much experience because you’re competing with so many other students just to get into the lab.”
A department characterized by networking
Jain and Ganjoo are two of a half-dozen researchers with whom Simens worked at Lehigh.
David Ackland, a research scientist and electron microscopy specialist, gave Simens her first training on Lehigh’s electron microscopes, which form the most comprehensive university collection of their kind in the U.S.
Rui Almeida, professor of materials science and engineering at the Instituto Superior Técnico in Lisbon, Portugal, helped Simens examine glass at the atomic level using SEM. Almeida is a visiting scientist at the IMI-NFG.
For her nanotechnology research project, Simens worked with Lehigh professors Christopher Kiely and Slava Rotkin to measure the transport properties of carbon nanotubes. Kiely, a professor of materials science and engineering, directs the nanocharacterization laboratory in Lehigh’s Center for Advanced Materials and Nanotechnology. Rotkin, assistant professor of physics, is co-editor of Applied Physics of Carbon Nanotubes
(2005), which explores the potential applications of nanotubes to electronics, lasers and medicine.
Simens’ appreciation of the powers of electron microscopy—and the care required to utilize those powers—deepened as she delved into her nanotube project. On the project, she prepared samples for the three-year-old JEOL 2200FS transmission electron microscope (TEM), one of two electron microscopes at Lehigh that are fitted with an aberration-correction device. The elite instruments enable scientists to determine the chemical identity of individual atoms in crystalline materials.
Advances in electron microscopy, says Simens, make it possible to study the electronic properties of carbon nanotubes in real time under a TEM.
“You can disperse [deposit] a nanotube onto a substrate and place it in a TEM,” says Simens, “and then apply a current and watch in real time to see how the nanotube reacts under a high voltage.”
To make the contact between the electric current and the nanotube, Simens used a focused ion beam and a platinum wire measuring 4 microns wide to connect the nanotube specimen with evaporated gold on each side of the specimen.
Working with the nanotube requires great precision and patience, Simens says, because the tube does not disperse onto the substrate in a predictable manner.
“There’s a lot we had to figure out,” says Simens. “Where to put the gold, how thick the gold should be, how to use FIB effectively, and how to disperse the nanotube without getting tangles and clumps that prevent us from measuring the electrical properties.
“This is a very good technique but difficult to master. It can take three hours to set up all the conditions just to lay down the two platinum wires.”
Life beyond materials science
Simens found an outlet from the rigors of research in Lehigh’s department of music. She took private piano lessons for three years and played alto sax in the Wind and Jazz Ensembles.
“The music department is very accommodating for non-music majors,” she says. “I’ve been playing piano since I was 5 years old, and it’s something I can’t not do. The university paid half the cost of my private lessons.
“The Wind Ensemble is really good. We recorded CDs, which I sent home to my parents. And the director of the Jazz Ensemble brought in great professional musicians from New York to teach us.
“I couldn’t have asked for a better undergraduate degree program. I’ve had the best at Lehigh.”
After graduating from Lehigh on May 22, Simens is planning this summer to work again at the National Center for Electron Microscopy. Next fall, she will enroll as a graduate student at Stanford.
“I definitely want to continue characterizing materials with electron microscopy,” she says. “I’ve worked with nanomaterials and glass. I’d like to learn more about them, and investigate biomedical materials as well.”