SBIR Phase I: Development of Large-Area Crystal-Aligned Substrates for Epitaxial Graphene

这个小型企业创新研究(SBIR)第一阶段项目解决了对石墨烯薄膜衬底的需求。石墨烯是一种独特的二维材料，被称为奇迹材料？由于其特殊的结构和电子性质，可以在许多应用中使用。然而，石墨烯是一种相对较新的材料，因此仍不能在大范围内重复制造。通过碳化硅表面分解和铜等催化金属上的化学气相沉积，在单晶上制备了高度完美的石墨烯外延薄膜。但是？外延生长？石墨烯原子与衬底配准的位置受到单晶衬底要求的限制。由于衬底中的颗粒失配，沉积在标准多晶材料上的石墨烯的电子性能并不是最优的。在这个项目中，我们利用离子束辅助沉积技术在玻璃和金属箔等各种表面上制备类似单晶的涂层。我们探索这些人工取向的薄膜来生产大面积的衬底，用于外延石墨烯的沉积。这种衬底将使人们能够在许多不同的表面上沉积高性能的外延石墨烯，而不需要刚性的单晶衬底。该项目的更广泛的影响/商业潜力是为大面积制造高质量的石墨烯薄膜提供一种技术。石墨烯具有极高的导电性、光学透明性和机械稳定性等独特的性能组合，使其成为光伏、显示器和其他光电子器件中透明电极的极佳候选材料。然而，仍然需要一种在各种不同的表面上提供大面积高性能石墨烯的技术。通过提供一种可扩展的晶体对齐方法？在薄膜沉积过程中，离子束薄膜对准技术可以反过来使大面积外延石墨烯薄膜得以生产。这些石墨烯薄膜的质量应该接近那些在小单晶片上制造的薄膜。这种晶体定向模板的使用已经被证明用于外延超导薄膜，该薄膜用于制造千米长的高温超导线。

This Small Business Innovation Research (SBIR) Phase I project addresses the need for substrates for graphene films. Graphene is a unique two-dimensional material that has been called the ?miracle material? because of its extraordinary structural and electronic properties that can be used in many applications. However, graphene is a relatively new material and as such is still not reproducibly fabricated in large areas. Highly perfect epitaxial graphene films have been synthesized on single crystals via surface decomposition on silicon carbide and by chemical vapor deposition on catalytic metals such as copper. However ?epitaxial growth? where graphene atoms are in registry with the substrate is limited by the single-crystal substrate requirement. Electronic properties of graphene deposited on standard polycrystalline materials are not optimal due to grain mismatch in the substrate. In this project we utilize ion-beam assisted deposition technology to make single-crystal like coatings on a variety of surfaces such as glass and metal foils. We explore these artificially aligned films to produce large area substrates for deposition of epitaxial graphene. Such substrates would enable one to deposit high-performance epitaxial graphene on many different surfaces without the need for rigid single-crystal substrates.The broader impact/commercial potential of this project is to provide a technology for large-area fabrication of high-quality graphene films. Graphene offers a singular combination of properties such as very high conductivity, optical transparency, and mechanical robustness, making it an excellent candidate for transparent electrodes in photovoltaics, displays, and other optoelectronic devices. However, what is still needed is a technology for providing large-area high-performance graphene on a variety of different surfaces. By providing a scalable method of ?crystal-aligned? film deposition, the ion-beam film aligning technology can in turn enable large-area epitaxial graphene films to be produced. These graphene films should approach the quality of those made on small single-crystal wafers. Use of such crystal-aligned templates has already been proven for epitaxial superconducting films that are used to manufacture high temperature superconductor wire in kilometer lengths.