DISSERTATION DEFENSE
Aditha Senarath, Interdisciplinary Materials Science Program
*under the supervision of Josh Caldwell and Ron Schrimpf
“GaN for Space and Power Electronics: Radiation Effects Study and Development of a Nano-Optical Probe for Characterization”
07.11.25 | 9:00 am | FGH 132 | Zoom
For decades, the semiconductor industry has followed Moore’s Law, predicting a doubling of chip power every two years by doubling transistor density. However, as traditional silicon-based technologies approach their performance and scalability limits, especially in high-power and harsh-environment applications. Wide-bandgap (WBG) semiconductors, such as Gallium Nitride (GaN), emerge as promising alternatives, offering fast switching speed and high voltage handling while being compatible with mature silicon chip manufacturing processes. Today, commercially available GaN-based chargers for consumer electronics and electric vehicles (EVs) deliver three times faster charging in devices that are three times smaller compared to silicon-based versions. However, in radiation-heavy environments such as space, GaN devices can degrade, raising questions about their long-term reliability.
My research focuses on two key objectives aimed at advancing the reliability and performance of GaN-based technologies for high-power and space applications. First, I investigated the effects of space radiation, particularly heavy ions, on GaN devices. Emphasis is placed on understanding the underlying damage mechanisms, particularly single-event effects (SEEs), and evaluating how design parameters, such as epitaxial layer thickness and edge termination, influence radiation tolerance. Additionally, comparative studies were conducted with silicon carbide (SiC), a mature WBG material, and gallium oxide (Ga₂O₃), an emerging candidate with potential for next-generation power and aerospace systems. The second focus of this work supports the continued miniaturization and performance enhancement of GaN power devices through the development of a nano-optical characterization technique based on scattering-type scanning near-field optical microscopy (s-SNOM). This method enables nanoscale spatial mapping of free carrier distributions and defects, while also providing localized spectral information. It leverages the interaction of infrared (IR) light with phonons and plasmons in doped GaN, offering insight into the fundamental light-matter interactions in GaN. These findings pave the way for the broader use of IR-based metrology tools in further advancing GaN technology.
Overall, this work reveals the effect of space radiation on GaN devices and introduces a nanoscale metrology platform for the development of GaN technology.
For more on Aditha’s research: Google Scholar/Aditha Senarath