Air Force research office honors two young engineering faculty

Author: William G. Gilroy and Nina Welding


The University of Notre Dame’s Vikas Tomar, assistant professor of aerospace and mechanical engineering, and Huili (Grace) Xing, assistant professor of electrical engineering, are two of the 39 engineers and scientists selected by the Air Force Office of Scientific Research (AFSOR) as part of the 2008 Young Investigator Program (YIP).

The program, which is only open to engineers and scientists at U.S. research institutions who have received a doctoral degree within the last five years, recognizes those who"show exceptional ability and promise for conducting basic research."This year’s YIP honorees will share approximately $12.1 million for research efforts over the next three years as outlined in their winning proposals.

As in previous years, competition for the award was very competitive. The ASFOR received 210 proposals encompassing a broad range of areas, including aerospace, chemical and materials sciences, physics and electronics, mathematics, information technologies, and life sciences.

Tomar, who joined the University in 2006, is investigating nanoscale thermal conduction and mechanical strength correlation in high-temperature ceramics as part of his efforts in the YIP. It coincides well with his work in the department’s Multiphysics Laboratory, where he is studying advanced ceramic matrix composites for use in energy plants. High-temperature ceramics that can work in extreme environmentsradiation or corrosionwould significantly benefit the coal industry and the development of nuclear power. For example, a simple increase in operating temperature (made possible through new high-temperature ceramics) can result in increased energy efficiency.

Although not part of his YIP research, Tomar also is studying biomaterials such as bone issue and biosensors. In one project, he is analyzing the structure-property relationships for bone tissue in different chemical environments to determine how different drugs affect the properties (including strength) of bone tissue.

In another research effort using molecular analyses, he is focusing on understanding the fundamental mechanisms that control biofunctional materials in extreme environments, such as a highly radioactive environment or sensitive physiological environment (a diseased part of the human body).

Xing’s YIP focuses on the quantum limits of nitride RF high-electron mobility transistors. Through experimental and theoretical approaches, she is investigating the physical origins of the upper limit of speed and power-handling capabilities in gallium-nitride based semiconductor transistors in order to advance the development of the next generation radio frequency applications.

Similar electronic devices, featuring reduced size and lower energy consumption, have already been employed in cell phone base stations. Xing envisions that high-electron mobility transistors could replace bulky power adapters with millimeter size chips, deployed in hybrid engines in automobiles, efficient terahertz (Thz) emitters and a host of other applications.

Xing’s project aligns with her interests in nitride semiconductors and electronic and optoelectronic devices. Her current research activities in this area include the integration of heterogeneous materials using direct wafer bonding, development of high energy efficiency green light emitting diodes for solid state lighting, as well as ultraviolet and infrared emitters, and Thz detection technologies for medical applications.

In addition to the nitride semiconductor family, Xing is working with a variety of electronic materials including III-V, II-VI compound semiconductors and graphene. Together with her colleagues in the newly established Midwest Institute for Nanoelectronics Discovery (MIND), she is searching for the next switch to replace current silicon transistors (silicon metal-oxide semiconductor field-effect transistors) in future computer chips. She has explored photo detectors amenable to inexpensive and large-scale fabrication using chemically synthesized CdSe (cadmium selenide) nanowires, especially their polarization sensitivity.

Xing has served as a faulty member since 2004.

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