In between two the extremes exists polycrystalline and paracrystalline phases, which are made up of a number of smaller crystals known as crystallites. The opposite of a single crystal sample is an amorphous structure where there the atomic position is limited to short range order only. Phys.A single crystal, also called monocrystal, is a crystalline solid in which the crystal lattice of the entire sample is continuous and unbroken to the edges of the sample, with no grain boundaries. Oak Ridge National Laboratory press release: Method to grow large single-crystal graphene could advance scalable 2D materials " Evolutionary selection growth of two-dimensional materials on polycrystalline substrates. This work also leveraged ORNL's Center for Nanophase Materials Sciences, a DOE Office of Science user facility. Microscopy work was supported as part of the Fluid Interface Reactions, Structures and Transport Center, an Energy Frontier Research Center. The research was supported by Oak Ridge National Laboratory's (ORNL's) Laboratory Directed Research and Development program ORNL's technology transfer royalty funded Technology Innovation Program Department of Energy's (DOE's) Advanced Research Projects Agency-Energy DOE Office of Science Basic Energy Sciences and the Office of Naval Research. ContactĬenter for Nanophase Materials Sciences, Oak Ridge National Funding Commercial application of graphene using the team's survival-of-the fittest, single-crystal growth method remains to be seen, but the researchers believe their method could also be applied to other promising two-dimensional materials, such as boron nitride and molybdenum disulfide. Moreover, they developed a theory-based model to explain which crystal orientations are fittest for survival. To characterize the quality of their single-crystal graphene, the researchers used a suite of techniques available at the Center for Nanophase Materials Sciences. This method allows production of single-crystal graphene on virtually any flat surface. In this controlled environment, the fastest growing orientation of graphene crystals overwhelms the others and gets evolutionarily selected into a single crystal, even on a polycrystalline substrate, without having to match the substrate's orientation. As the substrate moved underneath, the carbon atoms continuously assembled as a single crystal of graphene up to a foot in length. They carefully controlled the local deposition of the hydrocarbon molecules, bringing them directly to the edge of the emerging graphene film. The researchers sprayed a gaseous mixture of hydrocarbon precursor molecules onto a metallic, polycrystalline foil. SummaryĪ research team used chemical vapor deposition-with a twist-to localize control of the synthesis process and allow evolutionary, or self-selecting, growth under optimal conditions to produce a large, single-crystal-like sheet of graphene. ![]() It is promising for improving sensors, fuel cells, solar cells, and electronics. Graphene has unprecedented strength and high charge carrier mobility. The materials are needed for long-awaited applications. The novel technique may open new doors for growing high-quality sheets of materials. This method, which produces a single layer of graphene, relies on harnessing a "survival of the fittest" competition among graphene crystals. Researchers produced large, single-crystal-like graphene films more than a foot long using a new method they developed. The ScienceĪlthough thin layers of graphene and other two-dimensional materials can be made on the small scale required for research, to be useful these materials must be manufactured on a much larger scale. The fastest growing graphene (blue) overwhelms graphene lattices of other orientations (red and green) and gets "evolutionarily selected" into a single crystal, even on a surface made from different (blue, green, and red) crystals. A spray jet directs chemical vapor deposition of a foot-long single layer of graphene on a moving surface (gold).
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