基于分子束外延生长的石墨烯-硅异质结的设计制备、物性调控和原位同步辐射研究

The zero-bandgap of graphene limits its further applications in electronics or optoelectronics. Therefore, it is a big challenge to use graphene to replace silicon completely. However, it could be used to improve silicon-based devices or develop novel devices with new physical mechanism by incorporating graphene into silicon. Based on our previous investigations, united with related stations at Beijing Synchrotron Radiation Facility (BSRF), we proposed the following studies: (1) Through tuning the interface structures, we would systematically design and fabricate graphene-silicon heterostructures by Molecular Beam Epitaxy (MBE) techinique. (2) We would study the novel physical properties of the graphene-silicon heterostructures, and the law of their physical properties with the variation of their interface structures. (3) By using synchrotron-radiation angle-resolved photoemission spectroscopy and near edge X-ray abostption fine structure (ARPES&NEXAFS), we would study the electron states and energy bandgap structure of the heterostructures on the interface. And combing the interface structures and physical properties, we would explore the microscopic mechanism of the physical properties’ origination. Through these studies, it is expected to exploit the physical properties and their originated physical mechanism of the graphene-silicon heterostructures, and to be helpful on the design of high-performance graphene-silicon heterostructure based electronics, optoelectronics, and magnetoelectronics.

石墨烯的零带隙结构使石墨烯代替硅用在电子或光电子领域中具有很大的挑战，因而通过把石墨烯和硅耦合，改进硅器件的物理性能或者发展具有优异物理性能的石墨烯-硅异质结器件具有重要的研究意义。基于此，在前期研究的基础上，联合北京同步辐射相关实验站，拟进行以下研究：（1）基于MBE技术在Si、h-BN/Si和Oxide/Si衬底上生长石墨烯，结合界面结构调制，系统性地设计制备石墨烯-硅异质结结构；（2）研究石墨烯-硅异质结的新奇物理特性，以及界面结构对其物理性能的调制规律；（3）通过同步辐射角分辨光电子能谱与软x射线吸收谱相结合，原位研究异质结界面电子态和能带结构；结合界面结构和物理性能，研究异质结物理性能产生的微观机制。通过这些研究，有望揭示石墨烯-硅异质结的新奇物理特性及其产生的微观机制，为进一步发展高性能的石墨烯-硅异质结电子、光电子、磁电子等纳米器件奠定基础，并有力提升大科学装置的研究能力。

利用机械剥离法构建了一种新型石墨烯/硅异质结，并实现了整个异质结的界面调控；开发并制备了一种新型黑磷复合场效应晶体管，器件显示出两种非易失性的运行状态（PP+P和PNP）。利用该器件构建了一种依靠背电压脉冲驱动的可以实现简单与非逻辑功能的电路；探索了垂直石墨烯墙内部缺陷态的变化机制同时找到一种简单有效的方法来调控内部的缺陷态，并基于同步辐射实验提出一种表征垂直石墨烯墙内部边缘型缺陷的测试手段。通过改变氩刻时间和热处理温度，得到了一中良好的处理Ag（111）单晶表面的工艺，通过采用合理的生长时间制备出了纯（R3×R3）相的硅烯结构，基于同步辐射的XPS与ARPES表征手段，研讨了这种相硅烯的生长机制，同时证实了实际中（R3×R3）相的硅烯具有理论计算中各项优异的物理特性，其是目前最接近自支撑硅烯的超结构。研究获得了一些有意义的研究成果，较圆满地完成了项目任务书所列指标。