MSE Seminar: “Room Temperature Defect Control with the Electron Wind Force”

Details

Abstract

Since the Bronze Age, we have been controlling defects in materials with heat energy. Because thermal diffusion is random in nature, the process requires elevated temperature and a long time.

In this presentation, we will explore the efficacy of the electron wind force in room temperature defect control. Electron wind force is a mechanical stimulus that acts only on defects as high-energy electrons lose their momentum in an electron-defect encounter. It is well-studied as a damage phenomenon, but we explore its beneficial side in three classes of materials systems.

In electronic materials and devices, we demonstrate how electron wind force mitigates the defects to (1) rejuvenate transistors and diodes degraded from radiation or electrical stressing and (2) decrease susceptibility to radiation damage. In metals and alloys, we demonstrate active control of defects and microstructure by tuning grain size, rotation, defect density and phase transformation – all at unprecedented low temperatures. In our last class of examples, we chose nuclear graphite, a material that takes about 3000 Celsius for annealing, which we achieved at room temperature. We conclude that the electron wind force can be effective in in-situ or in-operando defect control in deployed devices to instill resilience by rejuvenation.

Bio

Aman Haque, Ph.D.

Professor, Mechanical Engineering
Penn State University

Dr. Aman Haque is a Professor of Mechanical Engineering at Penn State University. He received his Ph.D. in Mechanical Engineering from the University of Illinois at Urbana Champaign in 2002. His core expertise is nanofabrication, sensors and actuators, nanoscale thermo-physical behavior of materials and in-situ transmission electron microscopy, which he applies on the mechanics and multi-physics of nanoscale materials and interfaces. His current research involves a multi-physics approach towards reliability of silicon and power electronics devices. He is also interested in control of microstructure, defects, interfaces, and phases in nuclear and other engineering materials. He has published more than 150 journal papers in these areas.