CCB Seminar: Frances Ross (MIT)

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"Imaging crystal growth and phase transformations with environmental transmission electron microscopy"

Environmental TEM is a powerful tool to observe materials transformations as they take place, contributing to the twin aims of solving real-world problems and understanding fundamental materials phenomena. Central to the success of ETEM is the ability to replicate in situ the conditions relevant to the reaction of interest, spanning a range of sample temperatures, gas pressures and types, and liquids, and to correlate information from different spatially and temporally resolved signals. I will describe several strategies that we feel are helpful for increasing the impact of in situ experiments in areas ranging from cement mineral reactions to materials development for microelectronics. I will show how conventional ETEM can operate over a wide pressure range using a semi-open cell where both transmitted and secondary electrons are collected, and describe customized microscopes for reactions in ultra-high vacuum or toxic gases. Finally I will discuss sample design for higher throughput and beam control for material modification. With ongoing advances in hardware and processing, it seems evident that ETEM will continue to expand its role in addressing key problems and visualizing the fascinating details of materials processes.