Nanostructuring graphene by direct application of nanoporous polymers as lithographic masks

Graphene nanostructuring using self-assembled block copolymers (BC) is presently the most promising way for GAL fabrication. State-of-the-art polymer synthesis capability at DTU Nanotech offers an immediate possibility to improve by strict control of BC length scale and compositional uniformity, and augment the variety of nanostructures obtained by such a method. We propose to create polymer lithographic masks by following two main strategies: (1) cryo-microtoming of nanoporous polymers (NP) prepared from block copolymer precursors by selective etching of one of the blocks; (2) defoliating single polymer lamellae with nanostructures by exploiting self organization of di and triblock copolymers and selsective etching of one or two of the blocks. The masks in (1) will be prepared by improving sample preparation techniques for transmission electron microscopy (TEM) based on cryo-microtoming. The main challenge is to cut mm-size, 20 – 50 nm thin slices from 3D NP, with overall thickness variations of few nm. The masks in (2) will naturally be of thickness in the range of 10 – 40 nm depending on the length of the composing blocks.  

anionic_polymerization_setup kristoffer wp4 (b250).jpg 

Figure: Anionic polymerization setup for synthesis of block copolymers for graphene structuring. The orange solution is living polystyryl lithum in cyclohexane for in this case for polystyrene poly(dimethyl siloxane) diblock copolymers.




Kristoffer Almdal (Leader)
DTU Nanotech

Block copolymer synthesis
21 NOVEMBER 2019