磷烯基p-n结的理论设计及其电输运机理的研究

Developing nano-electronic devices based on low-dimensional functional materials to replace the conventional silicon-based semiconductor devices is one of the international frontier research hotspots. Phosphorene is a two-dimensional material with layer-dependent direct band gap, high carrier mobility, high on/off ratio, physical anisotropy and electronic inactiveness to defects. These extraordinary properties make phosphorene a new promising candidate to build nano-devices. The p-n junctions are the elementary "building blocks" of semiconductor electronic devices including diodes, transistors, solar cells, emitting diodes and integrated circuits. The electronic properties of phosphorene has been shown to be efficiently tuned by molecular adsorption and impurity doping. Thus, it is feasible to design the p-n junctions based on phosphorene. However, relevant researches are still deficient. In this project, phosphorene-based p-n junctions will be constructed by employing polar molecular adsorption and impurity doing. The electronic structure of the phosphorene-based p-n junctions will be investigated by first-principles calculation, and the mechanism of the charge and spin transport of the p-n junctions with molecular adsorption and impurity doping will be studied by nonequilibrium Green’s function method in combination with density functional theory, and then the p-n junctions with high-performance rectifying behavior and gas-sensitive property will be theoretically designed. This project will play a promoting role in the research on phosphorence-based nano-electronic devices.

发展低维功能材料来制备纳米电子器件从而替代传统硅基半导体器件是国际上前沿研究热点之一。磷烯为带隙可调的直接带隙二维半导体材料，具有高载流子迁移率、高开关比、各向异性、对缺陷不敏感等优异特性，有希望成为新一代制备纳米电子器件的候选材料。p-n结是二极管、晶体管、太阳能电池、发光二极管和集成电路等半导体电子器件的基本构成单元。研究显示磷烯电学性质可以通过分子吸附、杂质掺杂等方法有效调控，因而基于磷烯设计p-n结具有一定的可行性。然而，目前相关的研究尚比较缺乏。本项目将采用极性分子吸附和杂质掺杂的方法构建磷烯基p-n结。在第一性原理计算的基础上研究磷烯基p-n结的电子结构性质，利用基于密度泛函理论的非平衡格林函数方法，研究分子吸附和杂质掺杂的p-n结的电荷、自旋输运机理，从而在理论上设计具有高整流性能和气敏性能的p-n结。本项目的开展对于磷烯基纳米电子器件的研究具有一定的推动作用。

发展新型功能材料来制备纳米电子器件从而替代或补充传统硅基半导体器件是国际上竞相研究的热点之一。本研究基于密度泛函理论结合非平衡格林函数方法，理论设计了纳米电子器件，并研究了工作机理。具体开展了以下工作：（1）采用3d过渡金属原子（Sc-Ni）调节黑磷烯纳米带的电子性质及磁性，系统研究了3d过渡金属原子修饰的黑磷烯纳米带的自旋电子输运性质；（2）通过3d过渡金属原子（Sc-Ni）吸附，将磁性引入蓝磷烯纳米带，系统研究了金属原子的吸附情况和吸附体系的电子结构，进而设计基于蓝磷烯纳米带的自旋电子器件；（3）系统研究了通过4d过渡金属原子（Y-Mo）表面吸附和替位掺杂修饰的黑磷烯纳米带的电子性质、磁性和自旋输运性质；（4）石墨炔与不同金属电极（Cu、Au、Ni、Al、Ag等）接触的电子结构性质和输运性质，发现石墨炔与不同金属电极均形成了欧姆接触；（5）系统研究了二维半导体材料C2N与多种金属电极（Al、Ti、Ni、Cu、Ag、Pt、graphene等）接触之后的电子结构性质和输运性质，发现BN插层可使得C2N-Pt形成欧姆接触；（6）系统研究了基于金属-沙洛芬分子链的电子结构性质和输运性质；（7）系统研究了二维锰卟啉材料对H2S、CO、CO2、SO2、NO和NO的气敏性质，发现该材料对多种气体具有超高的灵敏度。