HMNTL Professor Shaloo Rakheja won a Faculty Early Career Development award from the National Science Foundation.
Rakheja is creating a computational framework for modeling III-nitride devices that could be used for future communications in extreme environments and at high frequencies. The project was motivated by the potential of III-nitride semiconductors, such as gallium nitride (GaN), to enable communication systems that work at higher frequencies, and across a broader range of temperatures, than today's systems.
The ability to work in extreme temperatures is needed so that devices can be used in areas ranging from cryogenic computing, which operates at around 4° Kelvin (−452°F), to sensors in deep oil wells, where temperatures can exceed 300° F—and perhaps even probes on the surface of Venus (864° F).
GaN is well-suited to meeting those challenges. However, “we haven’t even come close to the theoretical performance of GaN,” says Rakheja. “GaN promises so much! And we are only able to tap 20% of it, or 25% of it... And the reason is that the underlying physics is so unique, and we don’t fully understand GaN’s unique physics across broad frequency and temperature scales.”
She will develop a modeling framework that captures the complex physics of III-nitride materials. In particular, while existing simulators look at individual layers of the design hierarchy in isolation—meaning that a researcher can’t, for example, tweak the properties of a component material and then see the effect on circuit performance—she will “not just accurately model each layer, but enable interactions among layers.”
Existing solutions also assume room-temperature operation, and can’t look far beyond the frequency bands of today’s WiFi, which are around 2.4 GHz or 5 GHz. Rakheja’s framework will consider temperatures ranging from near absolute zero to the intense heat involved in aerospace and nuclear energy applications, and will look at frequencies of 100 GHz or beyond.
Ultimately, her work will make it possible to design devices and circuits with a solid theoretical understanding of how they will behave.