A Versatile fabrication platform for the exploration of new electronic materials and device structures

Date

2012-08-31

Authors

Collins, Daniel

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Abstract

Ubiquitous concerns in device fabrication are nanoscale positioning and the integration of complex combinations of diverse materials, many of which are extremely fragile. Frequently the completed device requires one or more of the constituent materials to be synthesized under suboptimal conditions, thus compromising the performance of the final structure. We have developed a platform to fabricate multi-component electrode cross-bar structures, where each material can be synthesized under its own ideal conditions. Furthermore, surface treatments and procedures that may otherwise be incompatible can be performed without concern of damage to the other constituent materials. We demonstrate our approach by fabricating an all carbon cross-bar electrode structure comprised of a graphene-graphite heterojunction. Initially, a graphene field effect transistor is fabricated using electron beam and optical lithography. The top graphite electrode is sculpted from a bulk piece of highly oriented pyrolytic graphite with the aid of a focused ion beam (FIB) and integrated micromanipulator system. This requires real-time shaping, cutting, accurate positioning (circa 100 nm precision) and wiring of the graphite top electrode. Electron transport characteristics of each electrode component and the final heterostructure have been measured. We show that this process is effective for the production of micron and submicron-scale multi-layer device structures including other materials such as gold. This fabrication scheme could be extended to produce novel structures such as mechanical resonators, and provide a foundation for combining fragile materials that have otherwise been incompatible with traditional fabrication techniques.

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Keywords

Graphene, Nanofabrication, Microfabrication, Graphite, FIB, Lithography

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