Facile and precise fabrication of 10-nm nanostructures on soft and hard substrates

One of the major challenges in the field of nanotechnology is the facile and inexpensive fabrication of <10-nm nanostructures with a defect-free and precise pattern over a large area. Nanoimprint lithography (NIL) is a nanopatterning method that allows low-cost, fast production, and large-scale fabrication, but it needs improvement with regard to achieving a high resolution over a large area, processing on soft substrates, and nanomaterial patterning. Herein, it is demonstrated 10-nm patterning on soft and hard substrates via an advanced nanoimprint process. With a 100-nm master mold, both soft and hard molds with reduced pattern sizes (50, 20, 10, and 5 nm) are first fabricated using atomic layer deposition (ALD) of Al₂O₃. After surface functionalization of the mold, nanoscale patterns are imprinted on both hard (Si) and soft polyethylene terephthalate substrates, which result in structures with a pattern size of 10 nm. Using a hybrid supporting layer poly(methyl methacrylate) (PMMA)/poly(vinyl alcohol) (PVA) and ion sputter etching, a well-defined and clean sub-10 nm nanostructure is achieved for the nanomaterial on the substrate after lift-off and thermal annealing processes. Using this method, a graphene nanoribbon 10 nm wide is fabricated. Our approach is suitable for the fabrication of devices and structures with a 10-nm-scale pattern over a large area.