V族烯纳米带电极分子器件计算设计与机理研究

The V group alkene represented by phosphorene are of grapheme-like two-dimensional layered materials, which are discovered recently. Due to their distinguished properties such as intrinsic band grap, high electron mobility, greater coherence length, electronic structure regulation conveniently, the V group alkene will play an important role in future microelectronics and photoelectron science field. Unlike the graphene, the V group alkene have specified thickness and anisotropy, therefore, the electronic structure of its nanoribbons can be modulated diversified. Based on previous research, by using the first-principle method based on the non-equilibrium Green’s function formalism and the density functional theory, we explore the effective methods of regulating electron transport properties in organic molecular devices which use the V group alkene nanoribbons as electrode. The main researched contents include: (1) the effect on the electronic structure by the doping , replacement, adsorbing, introducing defects on phosphorene, arsenene, antimonene nanoribbons. (2) the influence on the electronic transport properties of the molecular scale devices by the contact details between the organic single molecule and the V group alkene, the external environment of the device, and the structure change of the molecular and the V group alkene. (3)exploring the physical mechanism of the electronic transport in molecule device by interlayer interaction of the V group alkene nanoribbons，proposing the effective method to reduce or eliminate the coherence effect. The above studied conclusions can offer the physical models, performance parameters and theoretical basis for the real design of the novel molecular devices.

以黑磷为代表的V族烯是近期发现的类石墨烯二维层状材料,因其具有本征带隙、迁移率高、相干长度大、电子结构易调控等特点，在未来微电子，光电子等科学领域有着重要的应用前景。与石墨烯不同，V族烯具有一定的厚度且表现为各向异性，因此其纳米带的电子结构更为多样化也更具调控性。基于前期的研究工作基础，本项目采用密度泛函理论与第一性原理相结合的方法探索调控基于V族烯纳米带电极的有机分子器件电子输运性质的有效方法。重点研究：(1)掺杂、取代、吸附和缺陷等调控手段对磷烯，砷烯和碲烯纳米带电子结构的影响。(2)有机单分子与V族烯纳米带接触细节，器件外部环境扰动以及分子与V族烯纳米带构型变化对分子尺度器件电子输运性质的影响。(3)探索V族烯纳米带电极的层间相互作用对分子器件电子输运影响的物理机制，提出可以最大程度减小或者消除这种层间相干作用的有效方法。为设计新颖分子器件提供物理模型、性能参数和理论依据。

本项目采用非平衡格林函数与密度泛函理论相结合的第一性原理计算方法，聚焦V族烯纳米带电子结构、输运性质、器件计算设计开展工作。研究了边缘钝化、缺陷效应对砷烯纳米带电子结构和输运性质的影响，边缘钝化对砷烯纳米带电子结构影响显著,拓展边缘缺陷，负微分电阻行为的峰谷比可以明显增大。我们设计了一款蝴蝶结形砷烯纳米器件，这个器件具有显著的负微分电阻效应，具有超过103的巨大峰谷比，这为实验上制备高峰谷比的负微分电阻器件提供了模型和参数。研究了不同元素边缘钝化对两种不同结构的锑烯纳米带电子结构及输运性质的影响，研究发现不同元素边缘钝化也可以调控器件输运性能，这个结果拓宽了V族烯纳米带器件输运性能调控的方法。基于边缘钝化效应对V族烯纳米带电子结构的影响，我们构建了磷烯平面异质结，计算发现构建的模型器件其整流比可达103，在一些特定偏压下，整流比可高达107，这个工作为实验上制备基于二维材料的整流器件提供了模型和指导。研究了硫族气体吸附对锑烯纳米带电子结构和输运性能的影响，发现SO2、SO3的吸附将在费米能级附近增加新的能带，特别是SO2的吸附可以显著降低氢化锑烯纳米带的带隙，这将为有害气体SO2、SO3的气敏检测提供参考。研究了电极类型、连接基团、分子长度对分子器件输运性能的影响及机理分析，这为分子器件输运性能的调控提供了指导。项目执行期间发表标注本项目号的SCI学术论文4篇，另有4篇正在投稿和整理中。