Nanofabrication is the process of making functional structures with arbitrary patterns having nanoscale dimensions. Nanofabrication has been widely implemented commercially for improving microelectronic devices and information technology. However, the limitations of conventional lithography techniques in terms of resolution, capital and operational costs, and limited flexibility in terms of materials that can be patterned and fabricated have motivated the development of unconventional fabrication methods. Scanning probe lithography is one of these promising new fabrication methods, and it uses a scanning sharp probe to produce with nanoscale precision modifications on the surface of a material. This award supports fundamental research for the development of a scanning probe lithography method based on hot probes, which are used to thermo-chemically change the properties of a material at the nanoscale. This technology, called thermochemical nanolithography, has a broad range of applications, in particular to fabricate nanostructures in graphene, conductive polymers nanowires, DNA and protein nano-arrays. The research work is geared toward answering questions that can facilitate the wide scale use of thermochemical nanolithography and providing students with a unique interdisciplinary training that includes developing knowledge in materials science, spectroscopy, nano- and micro-fabrication, and surface science techniques. This will enable the team to augment the community's understanding of nanoscale processes and potentially provide inexpensive and robust tools to decrease the cost of entry into nanolithographic patterning.
Thermochemical nanolithography is a versatile atomic force microscopy based technique that can be used to fabricate nanostructures and nanoribbons of graphene-like materials via local thermal reduction of chemically modified graphene. Thermochemical nanolithography uses thermal probes to locally heat the surface of a material to produce a variety of nano-scale chemical reactions, which can be controlled in terms of spatial resolution and extent of chemical conversion, so that complex chemical gradients can be obtained. For applications in the next generation of electronic, sensor and energy nano-devices based on graphene-like materials, this project aims to address the following issues: (i) fabrication of defect-free graphene nanoribbons with control over size, length and positioning (registry) on arbitrary substrates; and (ii) nanoscale control of the chemistry of graphene and other materials nanostructures. The research team will use experiments, finite elements calculations and density functional theory simulations for understanding and controlling the nanoscale thermo-chemical modification of graphene-based materials to fabricate graphene nanoribbons of high quality with excellent control over positioning and size. Furthermore, this project aims at developing parallel (up to 100 probes) patterning using novel concepts of temperature control and software, with the goal of writing and then reading more than 1 million 10-nm pixels in 1 second.
