California Institute of Technology: Nai Chang Yeh Group
Published on Apr. 15, 2019
Customer Application
Plasma enhanced chemical vapor deposition (PECVD) is a technique used to deposit a thin film by inducing a plasma amongst gaseous chemical precursors. Within the plasma, ions and radicals react with other gaseous molecules and/or a surface to create a desired material. PECVD is especially prevalent in semiconductor fabrication, but also has applications in numerous material syntheses.
The Nai Chang Yeh Group laboratory uses PECVD to fabricate vertical graphene nanostructures (VGNs). VGNs are graphene-like materials that grow vertically with respect to their growth substrate and form a highly interconnected, porous graphene network with an extremely high surface area. In order to fabricate VGNs via PECVD, a cavity resonator is used that confines microwave frequency electromagnetic radiation, inducing a plasma in hydrogen/methane gas within a cylindrical reaction chamber.
In order to automate VGN production and increase yield, Zaber's X-LSQ600B motorized translation stage are used. Here, the motorized stage supports four microwave cavities, which create reactive plasmas in four separate chambers. The motorized stage is programmed to move the cavities in the reaction chambers, allowing automated production of graphene materials.
This application is possible because the Zaber motorized stage is robust; the microwave cavities are attached to stiff microwave power cables that create torque on the cavities as they move across the reaction chambers. However, the X-LSQ600B allows the cavities to easily move across the reaction chambers, maintaining their alignment.
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About Nai Chang Yeh Group at Caltech
The Nai Chang Yeh Group specializes in the fabrication, application, and characterization of two-dimensional and topological materials. Their PECVD synthesis of graphene yields the highest quality graphene to date in terms of electron mobility. They are also developing a scalable synthesis of high quality, large aspect ratio, graphene nanostructures, which, due to the abundant edge states and high electron mobility, are promising materials in electrochemical energy storage.
Visit the Nai Chang Yeg Group website at https://www.its.caltech.edu/~yehgroup/index.html.