Pushing the Limits of New Technologies
Researchers in the Texas State Materials Science, Engineering, and Commercialization program (MSEC) develop advanced materials for innovative solutions in the areas of energy, environment, health and security. A unique resource available to the program allows researchers to push the boundaries of new technologies and make improvements in specific fields like solar power, computer speed, infrared imaging and many others.
The Epitaxy Research Service Center (ERSC) is located in the Roy F. Mitte building and houses one of the largest molecular beam epitaxy (MBE) facilities at a U.S. institution of higher learning. MBE is a method for depositing a thin film of crystalline materials onto a semiconductor wafer or other surface. The process is able to produce layers as thin as a single atom, which can be stacked on top of one another layer-by-layer to create materials with unusual and desirable properties. Such materials can then be incorporated into device manufacturing, leading to huge improvements in fields like renewable energy or high-powered computing. The MBE process takes place in an ultra-high vacuum, where pure elements such as gallium, arsenic and cadmium are heated until they vaporize. The vaporized material then condenses on a wafer of target material. The growth rate of the new layer might only be nanometers per minute — not much faster than stalactites — but the importance is enormous.
In addition to the MBEs, the research center also houses a high temperature metalorganic chemical vapor deposition (MOCVD) reactor. While MBE works by physically depositing atoms on a surface, MOCVD grows materials using a chemical interaction between the wafer surface and a flow of gases onto it. White light LEDs, Blu-ray lasers and artificial diamond layers are grown by MOCVD.
“In terms of the tools available to researchers and the kinds of characterization we’re able to perform, Texas State stands above most other universities of a similar size and profile,” explains Dr. Mark Wistey, who recently joined the MSEC program.
Wistey’s work straddles the boundaries between applied physics, electrical engineering and materials science. He brought with him two National Science Foundation (NSF) grants to explore novel materials to improve computing power and increase photovoltaic efficiency. He and his team of graduate and undergraduate students test and guide their MBE experiments using Texas State’s LEAP supercomputer cluster, providing insight into materials that are cheaper, better and less toxic. “Our major strength in the ERSC is our ability to grow different kinds of materials on top of one another,” says Wistey, citing fellow MSEC professors Ed Piner and Tom Myers. “Then we test them experimentally and with computer models. Whether you’re purifying water with ultraviolet light, stimulating neurons with a red laser, or detecting explosives and people in the infrared, Texas State has materials for you.”
Prior to moving to Texas State, Wistey already had an impressive career, including work which led directly to spinoff company Solar Junction, which set the world record for solar cell efficiency. The two grants carried by the Wistey group were awarded by the NSF for basic research projects to help keep the U.S. competitive and profitable 10 to 20 years down the road. The group’s current goals include producing solar cells with over 50 percent efficiency and increasing the communication speed between multi-core CPUs by a factor of 10 while decreasing cost and energy usage. At the same time, Wistey includes many undergraduates in his research to give them firsthand exposure to cutting-edge technology, and to encourage student involvement in physics and engineering programs. These programs can be intimidating to younger students who want their work to have a direct impact on the world and who may feel like physics and engineering are less direct or more abstract than other fields. Working on exciting projects with real-world implications like those handled by the Wistey group can inspire young students and ensure retention.