Subcategory: Civil/Mechanical/Manufacturing Engineering
Danial Haei Najafabadi - Bunker Hill Community College
Co-Author(s): Young Jae Shin, Harvard university, Massachusetts Philip Kim, Harvard University, Massachusetts
Soon after discovery of graphene  (a single layer atomic thick graphite) and realizing its potential electronic properties, scientists started to explore 2D materials and their unique properties. 2D materials are few or single layer atomic thick material. These 2D sheets are connected together by out of plane van der Waals interactions. Some of by far known 2D materials are Graphene, Boron Nitride and Transitional Metal Dichalcogenides known as TMDCs with formula MX_2 in which M is transitional metal and X a Chalcogen . These 2D materials offer variety of properties such as semiconducting, magnetic, super conducting and so on. By stacking these 2D sheets in a careful manner we can create new artificial material with combined properties. These new materials could open up countless opportunities for next generation of flexible and transparent electronic and optoelectronic devices.
However, obtaining these material in atomic scale and stacking the layers with frequent success rate and without introducing contamination and defect in the process is yet an obstacle for researchers in this field. Mechanical exfoliation and chemical vaper deposition or CVD  are two commonly used methods by researchers. Here we report a new mechanical transfer method with modified Polycaprolactone (PCL) polymer developed by Dr. Young Jae Shin. This polymer is capable of picking up monolayers of graphene and Boron Nitride with high yield and it works in lower temperature range (bellow 57?C) compared to conventional polymer methods (PC and PPC). We successfully produced multiple stacks of 2D materials such as BN-G-BN, NbSe2-G-NbSe2, G-BN-G-BN and suspended Boron Nitride on Silicon Nitride substrate. This method showed a consistent replicability. Our future research will focus on optimizing this method for other 2D materials beyond Graphene and Boron Nitride and combining this method with vacuum transfer to minimize defects and contamination in the layers and potentially finding more clues on the source of such imperfections.
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Funder Acknowledgement(s): Acknowledgments: Special thanks to National Science Foundation, Dr. Philip Kim, Dr. Young Jae Shin, Dr. Kathryn Hollar, Sara Wenzel, Dr. JoDe Lavine, Prof. Gregory T Field, Prof. Sloane Wick, Kim group at Harvard University, Harvard John A. Paulson school of Engineering and Applied Science, Bunker Hill Community College and everyone who helped and supported to make this research possible.
Faculty Advisor: Young Jae Shin, firstname.lastname@example.org
Role: Stacking 2D materials on transfer station, Data collection, measurements, observations and analysis.