A Sealed Liquid Cell for In Situ Transmission Electron Microscopy of Controlled Electrochemical Processes

A microfabricated liquid cell that permits imaging and controlling of electrochemical processes in a transmission electron microscope (TEM) has been developed, and its capabilities are demonstrated. The liquid cell comprises two silicon chips with suspended electron-transparent silicon nitride membranes that encapsulate and hermetically seal a thin (~100 nm) liquid layer in the TEM high-vacuum environment. Up to 10 integrated electrodes with selectively exposed areas allow multiple experiments to be performed on the same chip, and the electrode geometry has been designed to facilitate the assembly of nanostructures or nanoscale patterning of thin-film materials on the electrodes. We demonstrate the cell operation by picoampere-level electrochemical control and imaging of copper electrodeposition. A wide variety of materials and electrolytes may be studied with this cell design, and the relatively small (~1 μm²) exposed electrode areas enable quantitative electrochemical control at low currents.