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Graduate Student Seminar - 04/06/2018

"Apparatus for Combined Nanoscale Gravimetric, Stress, and Thermal Measurements

by Kevin Palm

Advisor:  Associate Professor Jeremy Munday

Friday, April 6, 2018 -- 12:00 p.m.
Large Conference Room, 1207 Energy Research Facility

Abstract:  We present an apparatus that allows for the simultaneous measurement of mass change, heat evolution, reflectivity, and stress of thin film samples deposited on quartz crystal microbalances (QCMs). We show device operation at 24.85 ± 0.05°C under 9.31 ± 0.02 bar of H2 as a reactive gas. Using a 335 nm palladium film, we demonstrate that our apparatus quantifies curvature changes of 0.001 m-1 and, correspondingly, mass changes of 13 ng/cm2 in material systems exhibiting large stress fluctuations. We use a one-state nonlinear lumped element model to describe our system with thermal potentials measured at discrete positions by three resistance temperature devices (RTD) lithographically printed on the QCM. By inputting known heat amounts through lithographically defined Cr/Al wires, we demonstrate a 100 μW calorimetric sensitivity and 10 μW minimum detectable power. The capabilities of this instrument will allow for a more complete characterization of reactions occurring in nanoscale systems, such as the effects of hydrogenation in various metal films and nanostructures.

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