Postdoc/grad student positions are available in my group. The ideal candidate will have hands on experience with TEM and strong background in electronic materials/devices. Send me your CV highlighting these experiences
Mechanics & Microscopy of Materials & Devices
Our broader research interest is in the fundamentals of mechanics and physics of materials at multiple length-scales. Specifically, we study the effects of defects in electronic and engineering materials using high resolution microscopy. Recent interests encompass ionizing radiation effects on electronic devices, role of interfaces in wide bandgap devices, defect-electron interactions in nuclear, structural and battery electrode materials; multi-scale defects-property in nuclear graphite and developing experimental testbeds for in-situ (mainly TEM) studies. Our expertise is in mechanical (tension, bending, fracture, fatigue and creep) testing at the 1-100 nm length-scale. We also perform thermal conductivity (using the 3-omega technique and Raman) and electrical (diode/transistor) characterization from nanoscale to die-level specimens.
Secondly (and more importantly), can we control the microstructure with multi-physics coupling? This theme leads to fundamental understanding of the synthesis-microstructure relationship. The ulterior motive is to replace conventional thermal processing with multi-physics to achieve unprecedented microstructural control (such as room temperature annealing of metals or graphitization of carbon)
With focus on size dependent multi-physics phenomena, we study a wide variety of materials and systems for the coupling in the mechanical, thermal and electrical domains. This is performed on metals, semiconductors, ceramics, amorphous to graphitized carbon, irradiated nuclear materials to name a few.
Radiation Effects on Electronic Devices
We are working on single event effects and total ionization dose effects on the performance and reliability of electronic devices, such as GaN HEMTs and Ga2O3 diodes. The study involves both proton and heavy ion, gamma and more recently – neutron irradiation. Our focus is on how the mechanical domain influences the nucleation of damages. Mechanical stress localization (not to be confused with the average stress) can make devices vulnerable, particularly when coincided with the electrical field localizations. This hypothesis is expected to work better than single domain (just electrical domain) philosophy of device vulnerability. The mechanical domain is characterized by Raman and TEM. We see remarkable correlation between stress localization and damage nucleation in a variety of devices. The goal is to predict the spatial and temporal evolution of damage – and not just measure its path near failure conditions.
At the materials level, we apply similar approaches. Using our custom designed and fabricated MEMS devices under TEM/Raman/Infrared microscopes, we measure mechanical, electrical and thermal properties of electronic materials (from monolayer to thin films). The goal is to understand how does the <25 nm length-scale lead to unprecedented coupling among these domains.
We are working on non-traditional methods for active microstructural control. An example is metal annealing at near-room temperature. Another example is graphitization of carbon at near-room temperature. The ulterior motive is to develop energy saving materials (from electronic to structural) processing for desired microstructure & properties.
![]() |