单晶金属薄膜上大面积高质量石墨烯的制备和硅插层研究

Graphene is a potential successor to silicon as the preferred material for the active region of nanostructured electronics devices. However for many applications it is desirable to obtain high-quality and single-crystalline monolayer graphene over large areas, providing strong motivation for epitaxial growth of graphene on a Si substrate crystal. In this project, we are proposing to explore the epitaxial growth and Si intercalation structure of graphene at atomic scale on single crystalling metal epilayers on silicon and some oxide surfaces, by using ultra-high vacuum molecular beam epitaxy, pulsed laser deposition, and scanning tunneling microscopy as well as low-energy electrons diffraction system. Firstly, transition metal (Ru, Ir, Rh, Cu, Ni et al) single crystalline thinfilms of nanometer thickness will be prepared on MgO(111), sapphire α-Al2O3(0001), SrTiO3 (STO) oxide surface, and also on Si(111) surfaces with an ytti-stablized zirconia (YSZ) or STO buffer layers. Then high quality graphene can be formed by thermal decomposition of ethylene on these thin films at high temperature. It is essential to study the growth mechanism on epitaxial metals in order to assess the suitablity for graphene growth and control its orientation over large areas. Si atomic layers can then be intercalated underneath the graphene monolayer through controlled Si atoms deposition and annealing. Finally the structural morphologies, electronical and physical properties of graphene will be investigated with STM/STS, nanoprobe and devices measurements, as well as first principle calculations. Our approach of the epitaxial CVD growth and Si intercalation of graphene utilizing epitaxial metal fims as an underlayer, will give new insight on fabricating large-scale, continuous and single crystalline monolayer graphene for future high-performance electronic applications.

制备大面积高质量连续的石墨烯单晶材料，并与Si半导体材料和器件相结合对于其在未来纳米电子学中的应用具有非常重要的意义。在金属单晶薄膜上进行石墨烯单晶的外延生长，并在其界面制备Si插层结构是一个潜在可行的途径。本课题在超高真空环境中首先在带有氧化物（STO，YSZ）缓冲层的Si(111)表面，以及在MgO、α-Al2O3、STO氧化物表面上外延沉积过渡族金属(Ru,Ir,Cu,Ni等)单晶薄膜，然后通入碳氢化合物找到高温石墨化的反应条件，实现大面积高质量单晶石墨烯的可控制备。进一步沉积硅并控制退火条件，在金属衬底和石墨烯之间插入Si层，可以隔离其之间的相互作用。通过实验分析和器件测量，结合理论计算，研究大面积单晶石墨烯的形貌特征，电子结构，Si插层结构和输运特性等。本项目将给出在外延金属单晶薄膜上制备单晶石墨烯及其Si插层的关键工艺，掌握其生长规律及其结构－物性之关联，提供有价值的结论。

制备大面积高质量连续的石墨烯单晶材料，并与Si 半导体材料和器件相结合对于其在未来纳米电子学中的应用具有非常重要的意义。在金属单晶薄膜上进行石墨烯单晶的外延生长，并在其界面制备Si 插层结构是一个潜在可行的途径。本项目开展了在超高真空环境下在MgO、α-Al2O3、在带有YSZ氧化物缓冲层的Si(111)表面外延沉积生长过渡族金属Ir, Cu等单晶薄膜，然后实现了大面积高质量单晶石墨烯的可控制备。进一步沉积硅并控制退火条件，在金属衬底和石墨烯之间插入Si 层，可以隔离其之间的相互作用。通过STM/STS实验分析和测量，结合理论计算，研究大面积单晶石墨烯的形貌特征，电子结构，Si 插层结构和物理特性等。本项目给出了在外延金属单晶薄膜上制备单晶石墨烯及其Si 插层的关键工艺，掌握其生长规律及其结构－物性之关联，提供了有价值的结论。