金属/黑磷界面电子结构及载流子注入特性研究

Atomically thin black phosphorus (BP) has attracted increasing interest because of its unique properties such as energy gap tunability and ultrahigh carrier mobility. There have been investigations on the potential application of few-layer BP to such as field-effect transistors, photodetectors, spin valve, non-volatile charge-trap memoryetc. In all BP based devices, the charge transport process across metal/BP interface is important for optimum device operation. Compared with the theoretical studies, there are few experimental studies on the electronic structure of metal and black phosphorus. Here, we propose to investigate the interface electronic structure and energy level alignment between metal and BP using x-ray photoemission (XPS), ultraviolet photoemission spectroscopy (UPS), inverse photoemission spectroscopy (IPES), and angle resolved photoemission spectroscopy (ARPES) and control the energy alignment through interface modification and doping. It should also provide information on if it is possible to have non-Schottky barrier BP devices. We propose to study the carrier injection in metal/BP interface using time-resolved two photon photoemission spectroscopy (TR-2PPE). Our goal here is to understand the fundamental energetics and dynamics processes of charge injection across the interfaces. This work is designed to provide information about the working of BP devices. It will help to design and optimize the BP devices.

单元素二维原子晶体黑磷，由于其带隙可调、载流子迁移率高而受到广泛关注。继基于少层黑磷的场效应晶体管器件被发明以来，涌现出了许多基于黑磷的功能器件，如光电探测器、自旋阀、非易失性电荷陷阱存储器等。其中涉及的金属/黑磷界面直接关系到器件载流子的传输，进而影响器件性能。目前金属/黑磷界面电子结构的研究大多集中在理论方面，实验方面的报道还很少。本项目拟利用XPS、UPS、IPES、ARPES等表面分析技术，研究不同金属和黑磷之间的界面电子结构，在此基础上通过掺杂、加入修饰层等界面修饰方法对界面能级进行调控，为制备无肖特基势垒器件提供帮助；利用时间分辨双光子光电子能谱（TR-2PPE）对金属/黑磷界面中载流子注入及界面修饰对载流子注入的影响进行研究，实现对金属/黑磷界面载流子注入特性在微观上的理解。本项目的研究将为理解基于黑磷器件的工作原理提供关键信息，为充分实现黑磷在新型器件方面的创新提供支撑。

具有带隙可调、载流子迁移率高的二维材料黑磷备受关注，被广泛于光电探测器、自旋阀、非易失性电荷陷阱存储器等功能器件。在这些功能器件中，涉及到的金属/黑磷界面与器件的性能息息相关。本项目针对金属/界面电子结构展开相关研究，从非磁金属、磁性金属与黑磷构成的界面两方面着手，在研究其界面电子结构、能级排列、界面相互作用的基础上，通过界面修饰的方法对该界面进行优化与调控。本项目研究为深入了解界面在器件的作用提供思路，为设计基于黑磷的新型功能器件提供帮助。